【OH】Glossary Oracle词汇表（下）

Glossary

●　Oracle Automatic Storage Management disk group

A set of disk devices that Oracle Automatic Storage Management (Oracle ASM) manages as a unit. Each disk device can be an individual physical disk, a multiple disk device such as a RAID storage array or logical volume, or even a partition on a physical disk. You can create the Oracle ASM disk group when you create the Oracle Automatic Storage Management instance, or with Oracle Database Configuration Assistant.

●　Oracle Automatic Storage Management instance

The Oracle instance that manages an Oracle Automatic Storage Management disk group. It is created automatically when you install and configure Oracle Automatic Storage Management. See also Oracle system identifier (SID).

●　Oracle Automatic Storage Management

Enables creation of a single disk group from a collection of individual disk devices. It balances I/O to the disk group across all of the devices in the disk group. It also implements striping and mirroring to improve I/O performance and data reliability.

●　automatic undo management mode

A mode of Oracle Database in which undo data is stored in a dedicated undo tablespace. Unlike in manual undo management mode, the only undo management that you must perform is the creation of the undo tablespace. All other undo management is performed automatically.

●　connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination service and network route information.

The destination service is indicated by using its service name for the Oracle Database or its Oracle system identifier (SID) for Oracle release 11.2 databases. The network route provides, at a minimum, the location of the listener through use of a network address.

●　connect identifier

A name, net service name, or service name that resolves to a connect descriptor. Users initiate a connect request by passing a user name and password along with a connect identifier in a connect string for the service to which they want to connect, for example:

SQL> CONNECT user_name@connect_identifier Enter password: password

●　control files

Files that record the physical structure of a database and contain the database name, the names and locations of associated datafiles and online undo tablespace, the time stamp of the database creation, the current log sequence number, and checkpoint information.

●　default domain

The network domain within which most client requests take place. It can be the domain where the client resides, or a domain from which the client often requests network services. The default domain is also the client configuration parameter that determines what domain to append to unqualified network name requests. A name request is unqualified if it does not have a "." character within it.

●　directory naming

A naming method that specifies a directory server to resolve a net service name into a connect descriptor. The net service name is stored centrally in a directory server.

●　directory server

A Lightweight Directory Access Protocol (LDAP)-compliant directory server. A directory can provide centralized storage and retrieval of database network components, user and corporate policies preferences, user authentication, and security information, replacing client-side and server-side localized files.

●　external procedures

Procedure or function written in the C programming language and stored in a shared library. An Oracle server can call external procedures or functions using PL/SQL routines. For Oracle Database to connect to external procedures, the server must be configured with a net service name and the listener must be configured with protocol address and service information.

●　global database name

The full database name that uniquely distinguishes it from any other database in your network domain.

For example:

sales.us.example.com

where sales is the name you want to call your database and us.example.com is the network domain in which the database is located.

●　initialization parameter file

An ASCII text file that contains information needed to initialize a database and instance.

●　instance

Process associated with a running Oracle Database instance. When a database is started on a database server (regardless of the type of computer), Oracle Database allocates a memory area called the System Global Area and starts one or more Oracle Database processes. This combination of the System Global Area and Oracle Database processes is called an instance. The memory and processes of an instance manage the associated database's data efficiently and serve the users of the database.

●　installation type

A predefined component set that automatically selects which components to install. See "Oracle Database Editions" for a list of installation types available with each top-level component.

●　Interprocess Communication (IPC)

A protocol that client applications use that resides on the same node as the listener to communicate with the database. IPC can provide a faster local connection than TCP/IP.

●　listener

A process that resides on the server and whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

When a client requests a network session with a database server, a listener receives the actual request. If the client information matches the listener information, then the listener grants a connection to the database server.

●　listener.ora file

A configuration file for the listener that identifies the:

Listener name
Protocol addresses on which it is accepting connection requests
Services for which it is listening

The listener.ora file resides in the $ORACLE_HOME/network/admin directory.

An Oracle Database 11g Release 2 (11.2) does not require identification of the database service because of service registration. However, static service configuration is required for an Oracle Database 11g Release 2 (11.2) if you plan to use Oracle Enterprise Manager.

●　local naming

A naming method that resolves a net service name into a connect descriptor. This name is configured and stored in the tnsnames.ora file on each individual client.

●　manual undo management mode

A mode of the database in which undo blocks are stored in user-managed rollback segments.

●　naming method

A resolution method used by a client application to resolve a connect identifier to a network address when attempting to connect to a database service. Oracle Net Services supports the following naming methods:

Local naming
Directory naming
Host naming
External naming

●　net service name

A simple name for a service that resolves to a connect descriptor. Users initiate a connect request by passing a user name and password along with a net service name in a connect string for the service to which they want to connect:

SQL> CONNECT user_name@net_service_name Enter password: password

Depending on your needs, net service names can be stored in a variety of places, including:

Local configuration file, tnsnames.ora, on each client
Directory server
External naming service, such as Network Information Service (NIS) or Cell Directory Service (CDS)

●　OPS$

Acronym for operating system specific. The initialization file parameter OS_AUTHENT_PREFIX enables users to specify a prefix that Oracle uses to authenticate users attempting to connect to the database. Oracle concatenates the value of this parameter to the beginning of the user's operating system account name. When a connection request is attempted, Oracle compares the prefixed user name with Oracle user names in the database.

The default value of this parameter is "" (a null string), thereby eliminating the addition of any prefix to operating system account names. In earlier releases, OPS$ was the default setting.

●　ORACLE_BASE

ORACLE_BASE is the root of the Oracle Database directory tree. The Oracle Base directory is the top level directory that you can use to install the various oracle software products. You can use the same Oracle base directory for multiple installations. For example, /u01/app/oracle is an Oracle base directory created by the oracle user.

●　ORACLE_HOME

Corresponds to the environment in which Oracle Database products run. If you install an OFA-compliant database, using Oracle Universal Installer defaults, Oracle home (known as $ORACLE_HOME in this guide) is located beneath $ORACLE_BASE. The default Oracle home is db_n where n is the Oracle home number. It contains subdirectories for Oracle Database software executables and network files. See also Oracle home.

●　Oracle home

The directory path to install Oracle components (for example, /u01/app/oracle/product/11.2.0/db_n). You are prompted to enter an Oracle home in the Path field of the Specify File Locations window. See also ORACLE_HOME.

●　Oracle schema

A set of rules that determine what can be stored in an LDAP-compliant directory server. Oracle has its own schema that is applied to many types of Oracle entries, including Oracle Net Services entries. The Oracle schema for Oracle Net Services entries includes the attributes the entries may contain.

●　Oracle Net foundation layer

A networking communication layer that establishes and maintains the connection between the client application and server, and also exchanging messages between them.

●　protocol address

An address that identifies the network address of a network object.

When a connection is made, the client and the receiver of the request, such as the listener, or Oracle Connection Manager, are configured with identical protocol addresses. The client uses this address to send the connection request to a particular network object location, and the recipient "listens" for requests on this address. It is important to install the same protocols for the client and the connection recipient, and to configure the same addresses.

●　raw partitions

Portions of a physical disk that are accessed at the lowest possible disk (block) level.

●　redo log files

Files that contain a record of all changes made to data in the database buffer cache. If an instance failure occurs, then an administrator can use the redo log files to recover the modified data that was in memory.

●　repository

A set of tables located in any Oracle database accessible to the Oracle Management Server. Oracle Management Server uses a repository to store all system data and application data, information about the state of managed nodes distributed throughout the environment, and information about the separately licensable management packs.

●　service registration

A feature by which the PMON process (an instance background process) automatically registers information with a listener. Because this information is registered with the listener, the listener.ora file does not have to be configured with this static information.

Service registration provides the listener with the following information:

Service names for each running instance of the database
Instance names of the database
Service handlers (dispatchers and dedicated servers) available for each instance to enable the listener to direct a client's request appropriately.
Dispatcher, instance, and node load information

To enable the listener to determine which dispatcher can best handle a client connection's request. If all dispatchers are blocked, the listener can spawn a dedicated server for the connection.

This information enables the listener to determine how best to service a client connection request.

●　SID

The Oracle system identifier that distinguishes the database from all other databases on your computer. The SID automatically defaults to the database name portion of the global database name (sales in the example sales.us.example.com) until you reach eight characters or enter a period. You can accept or change the default value.

The SID can also refer to an Oracle ASM instance SID, available when you install Oracle Automatic Storage Management.

●　sqlnet.ora file

A configuration file for the client or server that specifies the:

Client domain to append to unqualified service names or net service names
Order of naming methods for the client to use when resolving a name
Logging and tracing features to use
Route of connections
External naming parameters
Oracle Advanced Security parameters

The sqlnet.ora file resides in $ORACLE_HOME/network/admin.

●　Secure Sockets Layer (SSL)

An industry standard protocol designed by Netscape Communications Corporation for securing network connections. SSL provides authentication, encryption, and data integrity using public key infrastructure (PKI).

●　SSL

See Secure Sockets Layer (SSL).

●　System Global Area

A group of shared memory structures that contain data and control information for an Oracle Database instance.

●　system identifier

See SID.

●　tablespace

A logical storage unit within a database. Tablespaces are divided into logical units of storage called segments, which are further divided into extents.

●　tnsnames.ora file

A configuration file that contains net service names mapped to connect descriptors. This file is used for the local naming method. The tnsnames.ora file resides in $ORACLE_BASE/network/admin.

●　undo tablespace

A tablespace that contains one or more undo segments. The creation of any other types of segment (for example, tables, indexes) in undo tablespaces is not allowed.

In the automatic mode, each Oracle instance is assigned one and only one undo tablespace. Each undo tablespace is composed of a set of undo files. Undo blocks are grouped in extents. At any point in time, an extent is either allocated to (and used by) a transaction table, or is free.

Blocks in undo tablespaces are grouped into the following categories:

File control blocks, bitmap blocks, and so forth used for space management
Undo segments containing transaction table blocks, undo blocks, and extent-map blocks used for transaction management
Free blocks that are unallocated to file control or undo segments

●　unqualified name

A net service name that does not contain a network domain.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　BFILEs

External binary files that exist outside the database tablespaces residing in the operating system. BFILEs are referenced from the database semantics, and are also known as external LOBs.

●　Binary Large Object (BLOB)

A large object data type whose content consists of binary data. Additionally, this data is considered raw as its structure is not recognized by the database.

●　Character Large Object (CLOB)

The LOB data type whose value is composed of character data corresponding to the database character set. A CLOB may be indexed and searched by the Oracle Text search engine.

●　coordinated universal time (UTC)

UTC was formerly known as Greenwich Mean Time.

●　Large Object (LOB)

The class of SQL data type that is further divided into internal LOBs and external LOBs. Internal LOBs include BLOBs, CLOBs, and NCLOBs while external LOBs include BFILEs.

●　National Character Large Object (NCLOB)

The LOB data type whose value is composed of character data corresponding to the database national character set.

●　PL/SQL

Oracle procedural language extension to SQL.

●　primary key

The column or set of columns included in the definition of a table's PRIMARY KEY constraint.

●　UTC

UTC (Coordinated Universal Time) was formerly known as Greenwich Mean Time.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　additive

Describes a fact (or measure) that can be summarized through addition. An additive fact is the most common type of fact. Examples include sales, cost, and profit. Contrast with nonadditive and semi-additive.

●　advisor

See SQL Access Advisor.

●　aggregate

Summarized data. For example, unit sales of a particular product could be aggregated by day, month, quarter and yearly sales.

●　aggregation

The process of consolidating data values into a single value. For example, sales data could be collected on a daily basis and then be aggregated to the week level, the week data could be aggregated to the month level, and so on. The data can then be referred to as aggregate data. The term aggregation is synonymous with summarization, and aggregate data is synonymous with summary data.

●　ancestor

A value at any level higher than a given value in a hierarchy. For example, in a Time dimension, the value 1999 might be the ancestor of the values Q1-99 and Jan-99.

●　attribute

A descriptive characteristic of one or more levels. For example, the product dimension for a clothing manufacturer might contain a level called item, one of whose attributes is color. Attributes represent logical groupings that enable end users to select data based on like characteristics.

Note that in relational modeling, an attribute is defined as a characteristic of an entity. In Oracle Database 10g, an attribute is a column in a dimension that characterizes each element of a single level.

●　cardinality

From an OLTP perspective, this refers to the number of rows in a table. From a data warehousing perspective, this typically refers to the number of distinct values in a column. For most data warehouse DBAs, a more important issue is the degree of cardinality.

●　change set

A set of logically grouped change data that is transactionally consistent. It contains one or more change tables.

●　change table

A relational table that contains change data for a single source table. To Change Data Capture subscribers, a change table is known as a publication.

●　child

A value at the level under a given value in a hierarchy. For example, in a Time dimension, the value Jan-99 might be the child of the value Q1-99. A value can be a child for more than one parent if the child value belongs to multiple hierarchies.

●　cleansing

The process of resolving inconsistencies and fixing the anomalies in source data, typically as part of the ETL process.

●　Common Warehouse Metadata (CWM)

A repository standard used by Oracle data warehousing, and decision support. The CWM repository schema is a standalone product that other products can share—each product owns only the objects within the CWM repository that it creates.

●　cross product

A procedure for combining the elements in multiple sets. For example, given two columns, each element of the first column is matched with every element of the second column. A simple example is illustrated as follows:

Col1   Col2   Cross Product
----   ----   -------------
a      c      ac
b      d      ad
bc
bd

Cross products are performed when grouping sets are concatenated, as described in Chapter 21, "SQL for Aggregation in Data Warehouses".

●　data mart

A data warehouse that is designed for a particular line of business, such as sales, marketing, or finance. In a dependent data mart, the data can be derived from an enterprise-wide data warehouse. In an independent data mart, data can be collected directly from sources.

●　data source

A database, application, repository, or file that contributes data to a warehouse.

●　data warehouse

A relational database that is designed for query and analysis rather than transaction processing. A data warehouse usually contains historical data that is derived from transaction data, but it can include data from other sources. It separates analysis workload from transaction workload and enables a business to consolidate data from several sources.

In addition to a relational database, a data warehouse environment often consists of an ETL solution, an analytical SQL engine, client analysis tools, and other applications that manage the process of gathering data and delivering it to business users.

●　degree of cardinality

The number of unique values of a column divided by the total number of rows in the table. This is particularly important when deciding which indexes to build. You typically want to use bitmap indexes on low degree of cardinality columns and B-tree indexes on high degree of cardinality columns. As a general rule, a cardinality of under 1% makes a good candidate for a bitmap index.

●　denormalize

The process of allowing redundancy in a table. Contrast with normalize.

●　derived fact (or measure)

A fact (or measure) that is generated from existing data using a mathematical operation or a data transformation. Examples include averages, totals, percentages, and differences.

●　detail

See: fact table.

●　detail table

See: fact table.

●　dimension

The term dimension is commonly used in two ways:

A general term for any characteristic that is used to specify the members of a data set. The three most common dimensions in a sales-oriented data warehouse are time, geography, and product. Most dimensions have hierarchies.
An object defined in a database to enable queries to navigate dimensions. In Oracle Database 10g, a dimension is a database object that defines hierarchical (parent/child) relationships between pairs of column sets. In Oracle Express, a dimension is a database object that consists of a list of values.

●　dimension table

Dimension tables describe the business entities of an enterprise, represented as hierarchical, categorical information such as time, departments, locations, and products. Dimension tables are sometimes called lookup or reference tables.

●　dimension value

One element in the list that makes up a dimension. For example, a computer company might have dimension values in the product dimension called LAPPC and DESKPC. Values in the geography dimension might include Boston and Paris. Values in the time dimension might include MAY96 and JAN97.

●　drill

To navigate from one item to a set of related items. Drilling typically involves navigating up and down through a level (or levels) in a hierarchy. When selecting data, you expand a hierarchy when you drill down in it, and you collapse a hierarchy when you drill up in it.

●　drill down

To expand the view to include child values that are associated with parent values in the hierarchy.

●　drill up

To collapse the list of descendant values that are associated with a parent value in the hierarchy.

●　element

An object or process. For example, a dimension is an object, a mapping is a process, and both are elements.

●　entity

Entity is used in database modeling. In relational databases, it typically maps to a table.

●　ETL

ETL stands for extraction, transformation, and loading. ETL refers to the methods involved in accessing and manipulating source data and loading it into a data warehouse. The order in which these processes are performed varies.

Note that ETT (extraction, transformation, transportation) and ETM (extraction, transformation, move) are sometimes used instead of ETL.

●　extraction

The process of taking data out of a source as part of an initial phase of ETL.

●　fact

Data, usually numeric and additive, that can be examined and analyzed. Examples include sales, cost, and profit. Fact and measure are synonymous; fact is more commonly used with relational environments, measure is more commonly used with multidimensional environments. A derived fact (or measure) is generated from existing data using a mathematical operation or a data transformation.

●　fact table

A table in a star schema that contains facts. A fact table typically has two types of columns: those that contain facts and those that are dimension table foreign keys. The primary key of a fact table is usually a composite key that is made up of all of its foreign keys.

A fact table might contain either detail level facts or facts that have been aggregated (fact tables that contain aggregated facts are often instead called summary tables). A fact table usually contains facts with the same level of aggregation.

●　fast refresh

An operation that applies only the data changes to a materialized view, thus eliminating the need to rebuild the materialized view from scratch.

●　file-to-table mapping

Maps data from flat files to tables in the warehouse.

●　hierarchy

A logical structure that uses ordered levels as a means of organizing data. A hierarchy can be used to define data aggregation; for example, in a time dimension, a hierarchy might be used to aggregate data from the Month level to the Quarter level to the Year level. Hierarchies can be defined in Oracle as part of the dimension object. A hierarchy can also be used to define a navigational drill path, regardless of whether the levels in the hierarchy represent aggregated totals.

●　high boundary

The newest row in a subscription window.

●　level

A position in a hierarchy. For example, a time dimension might have a hierarchy that represents data at the Month, Quarter, and Year levels.

●　level value table

A database table that stores the values or data for the levels you created as part of your dimensions and hierarchies.

●　low boundary

The oldest row in a subscription window.

●　mapping

The definition of the relationship and data flow between source and target objects.

●　materialized view

A pre-computed table comprising aggregated or joined data from fact and possibly a dimension table. Also known as a summary or aggregate table.

●　measure

See fact.

●　metadata

Data that describes data and other structures, such as objects, business rules, and processes. For example, the schema design of a data warehouse is typically stored in a repository as metadata, which is used to generate scripts used to build and populate the data warehouse. A repository contains metadata.

Examples include: for data, the definition of a source to target transformation that is used to generate and populate the data warehouse; for information, definitions of tables, columns and associations that are stored inside a relational modeling tool; for business rules, discount by 10 percent after selling 1,000 items.

●　model

An object that represents something to be made. A representative style, plan, or design. A model can also be metadata that defines the structure of the data warehouse.

●　nonadditive

Describes a fact (or measure) that cannot be summarized through addition. An example includes Average. Contrast with additive and semi-additive.

●　normalize

In a relational database, the process of removing redundancy in data by separating the data into multiple tables. Contrast with denormalize.

The process of removing redundancy in data by separating the data into multiple tables.

●　OLTP

See: online transaction processing (OLTP).

●　online transaction processing (OLTP)

Online transaction processing. OLTP systems are optimized for fast and reliable transaction handling. Compared to data warehouse systems, most OLTP interactions will involve a relatively small number of rows, but a larger group of tables.

●　parallelism

Breaking down a task so that several processes do part of the work. When multiple CPUs each do their portion simultaneously, very large performance gains are possible.

●　parallel execution

Breaking down a task so that several processes do part of the work. When multiple CPUs each do their portion simultaneously, very large performance gains are possible.

●　parent

A value at the level above a given value in a hierarchy. For example, in a Time dimension, the value Q1-99 might be the parent of the child value Jan-99.

●　partition

Very large tables and indexes can be difficult and time-consuming to work with. To improve manageability, you can break your tables and indexes into smaller pieces called partitions.

●　pivoting

A transformation where each record in an input stream is converted to many records in the appropriate table in the data warehouse. This is particularly important when taking data from nonrelational databases.

●　publication

A relational table that contains change data for a single source table. A Change Data Capture publisher refers to a publication as a change table.

●　publication ID

A publication ID is a unique numeric value that Change Data Capture assigns to each change table defined by a publisher.

●　publisher

Usually a database administrator who is in charge of creating and maintaining schema objects that make up the Change Data Capture system.

●　query rewrite

A mechanism to use a materialized view (which is precomputed) to quickly answer queries.

●　refresh

The mechanism whereby a materialized view is changed to reflect new data.

●　rewrite

See: query rewrite.

●　schema

A collection of related database objects. Relational schemas are grouped by database user ID and include tables, views, and other objects. The sample schemas sh are used throughout this Guide. Two special types of schema are snowflake schema and star schema.

●　semi-additive

Describes a fact (or measure) that can be summarized through addition along some, but not all, dimensions. Examples include headcount and on hand stock. Contrast with additive and nonadditive.

●　slice and dice

This is an informal term referring to data retrieval and manipulation. We can picture a data warehouse as a cube of data, where each axis of the cube represents a dimension. To "slice" the data is to retrieve a piece (a slice) of the cube by specifying measures and values for some or all of the dimensions. When we retrieve a data slice, we may also move and reorder its columns and rows as if we had diced the slice into many small pieces. A system with good slicing and dicing makes it easy to navigate through large amounts of data.

●　snowflake schema

A type of star schema in which each dimension table is partly or fully normalized.

●　source

A database, application, file, or other storage facility from which the data in a data warehouse is derived.

●　source system

A database, application, file, or other storage facility from which the data in a data warehouse is derived.

●　source tables

The tables in a source database.

●　SQL Access Advisor

The SQL Access Advisor helps you achieve your performance goals by recommending the proper materialized view set, materialized view logs, partitions, and indexes for a given workload. It is a GUI in Oracle Enterprise Manager, and has similar capabilities to the DBMS_ADVISOR package.

●　staging area

A place where data is processed before entering the warehouse.

●　staging file

A file used when data is processed before entering the warehouse.

●　star query

A join between a fact table and a number of dimension tables. Each dimension table is joined to the fact table using a primary key to foreign key join, but the dimension tables are not joined to each other.

●　star schema

A relational schema whose design represents a multidimensional data model. The star schema consists of one or more fact tables and one or more dimension tables that are related through foreign keys.

●　subject area

A classification system that represents or distinguishes parts of an organization or areas of knowledge. A data mart is often developed to support a subject area such as sales, marketing, or geography.

●　subscribers

Consumers of the published change data. These are normally applications.

●　subscription

A mechanism for Change Data Capture subscribers that controls access to the change data from one or more source tables of interest within a single change set. A subscription contains one or more subscriber views.

●　subscription window

A mechanism that defines the range of rows in a Change Data Capture publication that the subscriber can currently see in subscriber views.

●　summary

See: materialized view.

●　Summary Advisor

Replaced by the SQL Access Advisor.

●　target

Holds the intermediate or final results of any part of the ETL process. The target of the entire ETL process is the data warehouse.

●　third normal form (3NF)

A classical relational database modeling technique that minimizes data redundancy through normalization.

●　third normal form schema

A schema that uses the same kind of normalization as typically found in an OLTP system. Third normal form schemas are sometimes chosen for a large data warehouse, especially an environment with significant data loading requirements that is used to feed a data mart and execute long-running queries. Compare with snowflake schema and star schema.

●　transformation

The process of manipulating data. Any manipulation beyond copying is a transformation. Examples include cleansing, aggregating, and integrating data from multiple source tables.

●　transportation

The process of moving copied or transformed data from a source to a data warehouse. Compare with transformation.

●　unique identifier

An identifier whose purpose is to differentiate between the same item when it appears in more than one place.

●　update window

The length of time available for updating a warehouse. For example, you might have 8 hours at night to update your warehouse.

●　update frequency

How often a data warehouse is updated with new information. For example, a warehouse might be updated nightly from an OLTP system.

●　validation

The process of verifying metadata definitions and configuration parameters.

●　versioning

The ability to create new versions of a data warehouse project for new requirements and changes.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　atomically null object

An object whose value is NULL is called atomically null. An atomically null object is different from an object that has null values for all its attributes.

●　Binary Large Object (BLOB)

A large object data type whose value consists of raw binary data.

●　character large object (CLOB)

The large object (LOB) data type whose value is composed of character data corresponding to the database character set.

●　column object

An object that is stored as a column of a relational database table (as opposed to an object table). A column object can also be an attribute of another object. A column object is also known as a stored inline object or an embedded object.

●　embedded object attribute

An attribute of a column object.

●　dynamic method dispatch

A method call that is dispatched at run-time to the nearest method implementation when there are multiple implementations of the same method using overriding.

●　index-organized table IOT

A table organized by its index.

●　leaf-level scalar object

An object that is not a collection and is not composed of other types.

●　leaf-level scalar attribute

An attribute of a leaf-level scalar object.

●　literal invocation

An invocation where all arguments are literals or invocations of literal methods. Arguments cannot be variables.

●　materialized view

A view that contains both the query and its results.

●　multilevel collection type

Ccollection types whose elements are collection types, either directly or indirectly.

●　multiset operators

An operator that combines elements of two nested tables into a single nested table.

●　nested table

An unordered set of data elements of the same data type.

●　normalize

The process of removing redundancy in data by separating the data into multiple tables.

●　object column

A column of user-defined types or abstract data types (ADT)s .

●　object identifier

Identifier for a row object which can be either system-generated (default) or based on a primary key using the CREATE TABLE statement.

●　object instance

An instance of an object type. Also referred to as an object.

●　object table

A table in which each row represents an object. See row object.

●　object type

The type of the object instance. It is similar to a record that has methods. Object types are user-defined.

●　outer table

A table that contains a nested table.

●　pinning

Fetching.

●　PL/SQL

The Oracle procedural language extension to SQL.

●　polymorphism

Allows handling data types and methods generically using the same interface. In polymorphic overriding, subtypes redefine a method they have inherited. In polymorphic overloading, there may be several versions of the same method, with different parameters.

●　primary key

The column or set of columns specified in the PRIMARY KEY constraint of a table.

●　REF

An Oracle built-in data type that encapsulates references to row objects of a specified object type.

●　row object

An object that is stored in a complete row in an object table.

●　specializing

Adding new attributes or methods to a subtype that the parent supertype does not have, or changing the implementation of a method or methods.

●　stored procedure

A PL/SQL block that is stored in the database and can be executed from an application.

●　substitutability

A supertype is substitutable if one of its subtypes can substitute or stand in for it in a variable or column whose declared type is the supertype.

●　type evolution

The modification of a subtype of a type, typically using an ALTER statement.

●　VARRAY

An ordered set of data elements, that are of the same data type or a subtype of the declared data type.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　Oracle Automatic Storage Management disk group

●　Oracle Automatic Storage Management instance

●　Oracle Automatic Storage Management

●　automatic undo management mode

●　connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination service and network route information.

●　connect identifier

SQL> CONNECT user_name@connect_identifier Enter password: password

●　control files

●　default domain

●　directory naming

A naming method that specifies a directory server to resolve a net service name into a connect descriptor. The net service name is stored centrally in a directory server.

●　directory server

●　external procedures

●　global database name

The full database name that uniquely distinguishes it from any other database in your network domain.

For example:

sales.us.example.com

where sales is the name you want to call your database and us.example.com is the network domain in which the database is located.

●　initialization parameter file

An ASCII text file that contains information needed to initialize a database and instance.

●　instance

●　installation type

A predefined component set that automatically selects which components to install. See "Oracle Database Editions" for a list of installation types available with each top-level component.

●　Interprocess Communication (IPC)

A protocol that client applications use that resides on the same node as the listener to communicate with the database. IPC can provide a faster local connection than TCP/IP.

●　listener

A process that resides on the server and whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

●　listener.ora file

A configuration file for the listener that identifies the:

Listener name
Protocol addresses on which it is accepting connection requests
Services for which it is listening

The listener.ora file resides in the $ORACLE_HOME/network/admin directory.

●　local naming

A naming method that resolves a net service name into a connect descriptor. This name is configured and stored in the tnsnames.ora file on each individual client.

●　manual undo management mode

A mode of the database in which undo blocks are stored in user-managed rollback segments.

●　naming method

Local naming
Directory naming
Host naming
External naming

●　net service name

SQL> CONNECT user_name@net_service_name Enter password: password

Depending on your needs, net service names can be stored in a variety of places, including:

Local configuration file, tnsnames.ora, on each client
Directory server
External naming service, such as Network Information Service (NIS) or Cell Directory Service (CDS)

●　OPS$

The default value of this parameter is "" (a null string), thereby eliminating the addition of any prefix to operating system account names. In earlier releases, OPS$ was the default setting.

●　ORACLE_BASE

●　ORACLE_HOME

●　Oracle home

●　Oracle schema

●　Oracle Net foundation layer

A networking communication layer that establishes and maintains the connection between the client application and server, and also exchanging messages between them.

●　protocol address

An address that identifies the network address of a network object.

●　raw partitions

Portions of a physical disk that are accessed at the lowest possible disk (block) level.

●　redo log files

●　repository

●　service registration

Service registration provides the listener with the following information:

Service names for each running instance of the database
Instance names of the database
Service handlers (dispatchers and dedicated servers) available for each instance to enable the listener to direct a client's request appropriately.
Dispatcher, instance, and node load information

To enable the listener to determine which dispatcher can best handle a client connection's request. If all dispatchers are blocked, the listener can spawn a dedicated server for the connection.

This information enables the listener to determine how best to service a client connection request.

●　SID

The SID can also refer to an Oracle ASM instance SID, available when you install Oracle Automatic Storage Management.

●　sqlnet.ora file

A configuration file for the client or server that specifies the:

Client domain to append to unqualified service names or net service names
Order of naming methods for the client to use when resolving a name
Logging and tracing features to use
Route of connections
External naming parameters
Oracle Advanced Security parameters

The sqlnet.ora file resides in $ORACLE_HOME/network/admin.

●　Secure Sockets Layer (SSL)

●　SSL

See Secure Sockets Layer (SSL).

●　System Global Area

A group of shared memory structures that contain data and control information for an Oracle Database instance.

●　system identifier

See SID.

●　tablespace

A logical storage unit within a database. Tablespaces are divided into logical units of storage called segments, which are further divided into extents.

●　tnsnames.ora file

A configuration file that contains net service names mapped to connect descriptors. This file is used for the local naming method. The tnsnames.ora file resides in $ORACLE_BASE/network/admin.

●　undo tablespace

A tablespace that contains one or more undo segments. The creation of any other types of segment (for example, tables, indexes) in undo tablespaces is not allowed.

Blocks in undo tablespaces are grouped into the following categories:

File control blocks, bitmap blocks, and so forth used for space management
Undo segments containing transaction table blocks, undo blocks, and extent-map blocks used for transaction management
Free blocks that are unallocated to file control or undo segments

●　unqualified name

A net service name that does not contain a network domain.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　Component Object Model (COM)

A binary standard that enables objects to interact with other objects, regardless of the programming language that each object was written in

●　Distributed Component Object Model (DCOM)

An extension of COM that enables objects to interact with other objects across a network

●　dynamic-link library (DLL)

An executable file that a Windows application can load when needed

●　external procedure

A function written in a third-generation language (3GL), such as C, and callable from within PL/SQL or SQL as if it were a PL/SQL function or procedure

●　GUID

An identifier that uniquely identifies a COM object. GUID is an acronym for Globally Unique Identifier

●　IID

A GUID that identifies a COM interface

●　listener

The server process that listens for and accepts incoming connection requests from client applications. Oracle listener processes start up Oracle Database processes to handle subsequent communications with the client

●　listener.ora

A configuration file that describes one or more Transparent Network Substrate (TNS) listeners on a server

●　messaging application programming interface (MAPI)

A messaging architecture composed of a set of common application programming interfaces that enables multiple applications to interact with multiple messaging systems across a variety of hardware platforms

●　Optimal Flexible Architecture (OFA)

A set of file naming and placement guidelines for Oracle software and databases

●　Oracle COM Automation Feature

An Oracle feature that enables PL/SQL developers to programmatically manipulate COM objects through the IDispatch COM Automation interface

●　Oracle Net

The Oracle client/server communication software that offers transparent operation to Oracle tools or databases over any type of network protocol and operating system

●　PL/SQL

Oracle's procedural language extension to SQL

●　progID

A descriptive string that maps to a GUID

●　tnsnames.ora

A file that contains connect descriptors mapped to net service names. The file may be maintained centrally or locally, for use by all or individual clients

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　access path

The means by which data is retrieved from a database. For example, a query using an index and a query using a full table scan use different access paths.

●　asynchronous I/O

Independent I/O, in which there is no timing requirement for transmission, and other processes can start before the transmission has finished.

●　Automatic Workload Repository

Collects, processes, and maintains performance statistics for problem detection and self-tuning purposes.

●　Autotrace

Generates a report on the execution path used by the SQL optimizer and the statement execution statistics. The report is useful to monitor and tune the performance of DML statements.

●　bind variable

A variable in a SQL statement that must be replaced with a valid value, or the address of a value, in order for the statement to successfully execute.

●　block

A unit of data transfer between main memory and disk. Many blocks from one section of memory address space form a segment.

●　bottleneck

The delay in transmission of data, typically when a system's bandwidth cannot support the amount of information being relayed at the speed it is being processed. However, many factors can create a bottleneck in a system.

●　buffer

A main memory address where the buffer manager caches currently and recently used data read from disk. Over time, a buffer can hold different blocks. When a new block is needed, the buffer manager can discard an old block and replace it with a new one.

●　buffer pool

A collection of buffers.

●　cache

Also known as buffer cache. All buffers and buffer pools.

●　cache recovery

The part of instance recovery where Oracle Database applies all committed and uncommitted changes in the redo log files to the affected data blocks. Also known as the rolling forward phase of instance recovery.

●　Cartesian product

A join with no join condition results in a Cartesian product, or a cross product. A Cartesian product is the set of all possible combinations of rows drawn one from each table. Thus, for a join of two tables, each row in one table is matched in turn with every row in the other. A Cartesian product for more than two tables is the result of pairing each row of one table with every row of the Cartesian product of the remaining tables. All other types of joins are subsets of Cartesian products effectively created by deriving the product and then excluding rows that fail the join condition.

●　compound query

A query that uses set operators (UNION, UNION ALL, INTERSECT, or MINUS) to combine two or more simple or complex statements. Each simple or complex statement in a compound query is called a component query.

●　contention

When some process has to wait for a resource that another process is using.

●　dictionary cache

A collection of database tables and views containing reference information about the database, its structures, and its users. Oracle Database accesses the data dictionary frequently during the parsing of SQL statements. Two special locations in memory are designated to hold dictionary data. One area is called the data dictionary cache, also known as the row cache because it holds data as rows instead of buffers (which hold entire blocks of data). The other area is the library cache. All Oracle processes share these two caches for access to data dictionary information.

●　direct I/O

I/O which bypasses the buffer cache. See "PIO".

●　distributed statement

A statement that accesses data on two or more distinct nodes/instances of a distributed database. A remote statement accesses data on one remote node of a distributed database.

●　dynamic performance views

The views database administrators create on dynamic performance tables (virtual tables that record current database activity). Dynamic performance views are called fixed views because they cannot be altered or removed by the database administrator.

●　dynamic statistics

An optimization technique in which the database executes a recursive SQL statement to scan a small random sample of a table's blocks to estimate predicate selectivities.

●　enqueue

This is another term for a lock.

●　equijoin

A join condition containing an equality operator.

●　estimator

Uses statistics to estimate the selectivity, cardinality, and cost of execution plans. The main goal of the estimator is to estimate the overall cost of an execution plan.

●　execution plan

The combination of steps used by the database to execute a SQL statement. Each step either retrieves rows of data physically from the database or prepares them for the user issuing the statement. You can override execution plans by using hints.

●　EXPLAIN PLAN

A SQL statement that enables examination of the execution plan chosen by the optimizer for DML statements. EXPLAIN PLAN causes the optimizer to choose an execution plan and then to put data describing the plan into a database table.

●　fast full index scan

A full index scan in which the database reads the index blocks in no particular order. The database accesses the data in the index itself, without accessing the table.

●　full index scan

A scan of an index in which the database reads the entire index in order.

●　full table scan

A scan of table data in which the database sequentially reads all rows from a table and filters out those that do not meet the selection criteria. During full table scans the database scans all data blocks under the high water mark.

●　hash join

A join in which the database uses the smaller of two tables or data sources to build a hash table in memory. In hash joins, the database scans the larger table, probing the hash table for the addresses of the matching rows in the smaller table.

●　hint

An instruction passed to the optimizer through comments in a SQL statement. The optimizer uses hints to choose an execution plan for the statement.

●　index clustering factor

A measure of the row order in relation to an indexed value such as last name. The more order that exists in row storage for this value, the lower the clustering factor.

●　instance recovery

The automatic application of redo log records to data blocks after a database failure.

●　join

A query that selects data from multiple tables. A join is characterized by multiple tables in the FROM clause. Oracle Database pairs the rows from these tables using the condition specified in the WHERE clause and returns the resulting rows. This condition is called the join condition and usually compares columns of all the joined tables.

●　latch

A simple, low-level serialization mechanism to protect shared data structures in the System Global Area.

●　library cache

A memory structure containing shared SQL and PL/SQL areas. The library cache is one of three parts of the shared pool.

●　LIO

Logical I/O. A block read which may or may not be satisfied from the buffer cache.

●　literal

A constant value, written at compile-time and read-only at run-time. The database can access literals quickly and uses them when modification is not necessary.

●　mirroring

Maintaining identical copies of data on one or more disks. Typically, mirroring occurs on duplicate hard disks at the operating system level, so that if one disk becomes unavailable, the other disk can service requests without interruptions.

●　MTBF

Mean time between failures. A common database statistic important to tuning I/O.

●　nonequijoin

A join condition containing something other than an equality operator.

●　optimizer

Built-in database software that determines the most efficient way to execute a SQL statement. The query optimizer is made up of the query transformer, the estimator, and the plan generator.

The optimizer generates a set of potential execution plans for SQL statements, estimates the cost of each plan, calls the plan generator to generate the plan, compares the costs, and chooses the plan with the lowest cost. The database uses this approach when the data dictionary has statistics for at least one of the tables accessed by the SQL statements.

●　optimizer mode

The optimizer operates in either normal mode or tuning mode. In normal mode, the optimizer compiles the SQL and generates an execution plan. In tuning mode, the optimizer performs additional analysis and generates a series of actions, along with their rationale and expected benefit for producing a significantly better plan. When running in tuning mode, the optimizer is known as the Automatic Tuning Optimizer.

●　outer join

A join condition using the outer join operator (+) with one or more columns of one of the tables. Oracle Database returns all rows that meet the join condition. Oracle Database also returns all rows from the table without the outer join operator for which there are no matching rows in the table with the outer join operator.

●　paging

A technique for increasing the memory space available by moving infrequently-used parts of a program's working memory from main memory to a secondary storage medium, usually a disk. The unit of transfer is called a page.

●　parse

A hard parse occurs when a SQL statement is executed, and the SQL statement is either not in the shared pool, or it is in the shared pool but it cannot be shared. A SQL statement is not shared if the metadata for the two SQL statements is different. This can happen if a SQL statement is textually identical as a preexisting SQL statement, but the tables referred to in the two statements resolve to physically different tables, or if the optimizer environment is different.

A soft parse occurs when a session attempts to execute a SQL statement, and the statement is in the shared pool, and it can be used (that is, shared). For a statement to be shared, all data, (including metadata, such as the optimizer execution plan) pertaining to the existing SQL statement must be equally applicable to the current statement being issued.

●　parse call

A call to Oracle Database to prepare a SQL statement for execution. This includes syntactically checking the SQL statement, optimizing it, and building (or locating) an executable form of that statement.

●　parser

Performs syntax analysis and semantic analysis of SQL statements, and expands views (referenced in a query) into separate query blocks.

●　PGA

Program Global Area. A nonshared memory region that contains data and control information for a server process, created when the server process is started.

●　PIO

Physical I/O. A block read which could not be satisfied from the buffer cache, either because the block was not present or because the I/O is a direct I/O which bypasses the buffer cache.

●　plan generator

Tries out different possible plans for a given query so that the query optimizer can choose the plan with the lowest cost. It explores different plans for a query block by trying out different access paths, join methods, and join orders.

●　predicate

A WHERE condition in SQL.

●　query optimizer

See optimizer.

●　query transformer

Decides whether to rewrite a user query to generate a better query plan, merges views, and performs subquery unnesting.

●　RAID

Redundant arrays of inexpensive disks. RAID configurations provide improved data reliability with the option of striping (manually distributing data). Different RAID configurations (levels) are chosen based on performance and cost, and are suited to different types of applications, depending on their I/O characteristics.

●　row source generator

Receives the optimal plan from the optimizer and outputs the execution plan for the SQL statement. A row source is an iterative control structure that processes a set of rows in an iterated manner and produces a row set.

●　segment

A set of extents allocated for a specific type of database object, such as a table, index, or cluster.

●　selectivity

In a query, the measure of how many rows from a row set pass a predicate test, for example, WHERE last_name = 'Smith'.

●　simple query

A SELECT statement that references only one table and does not make reference to GROUP BY functions.

●　simple statement

An INSERT, UPDATE, DELETE, or SELECT statement that involves only a single table.

●　SGA

System Global Area. A memory region within main memory used to store data for fast access. Oracle database uses the shared pool to allocate SGA memory for shared SQL and PL/SQL procedures.

●　skewed data

Values with large variations in the number of duplicates.

●　SQL Compiler

Compiles SQL statements into a shared cursor. The SQL Compiler is made up of the parser, the optimizer, and the row source generator.

●　SQL profile

A collection of information that enables the query optimizer to create an optimal execution plan for a SQL statement.

●　SQL statements (identical)

Textually identical SQL statements do not differ in any way.

●　SQL statements (similar)

Similar SQL statements differ only due to changing literal values. If literal values were replaced with bind variables, then the SQL statements would be textually identical.

●　SQL Trace

A basic performance diagnostic tool to help monitor and tune applications running against the Oracle database. SQL Trace lets you assess the efficiency of the SQL statements an application runs and generates statistics for each statement. The trace files produced by this tool serve as input for TKPROF.

●　SQL tuning set (STS)

A database object that includes one or more SQL statements along with their execution statistics and execution context.

●　SQL*Loader

Reads and interprets input files. Use this tool to load large amounts of data.

●　Statspack

A set of SQL, PL/SQL, and SQL*Plus scripts that allow the collection, automation, storage, and viewing of performance data. This feature has been replaced by the Automatic Workload Repository.

●　striping

The interleaving of a related block of data across disks. Proper striping reduces I/O and improves performance.

Stripe depth is the size of the stripe, sometimes called stripe unit.
Stripe width is the product of the stripe depth and the number of drives in the striped set.

●　TKPROF

A diagnostic tool to help monitor and tune applications running against the Oracle database. TKPROF primarily processes SQL trace output files and translates them into readable output files, providing a summary of user-level statements and recursive SQL calls for the trace files. It can also assess the efficiency of SQL statements, generate execution plans, and create SQL scripts to store statistics in the database.

●　transaction recovery

The part of instance recovery where Oracle Database applies the rollback segments to undo the uncommitted changes. Also known as the rolling back phase of instance recovery.

●　UGA

User Global Area. A memory region in the large pool used for user sessions.

●　wait events

Statistics that are incremented by a server process/thread to indicate that it had to wait for an event to complete before being able to continue processing. Wait events are one of the first places for investigation when performing reactive performance tuning.

●　wait events (idle)

These events indicate that the server process is idle and waiting for work. Ignore these events when tuning because they do not indicate the nature of the performance bottleneck.

●　work area

A private allocation of memory used for sorts, hash joins, and other operations that are memory-intensive. A sort operator uses a work area (the sort area) to perform the in-memory sort of a set of rows. Similarly, a hash-join operator uses a work area (the hash area) to build a hash table from its left input.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　alert log

A file that contains important information and error messages that are generated during database operations.

●　authenticate

To verify the identity of a user, device, or other entity in a computer system, often as a prerequisite for allowing access to resources in a system.

●　authorization

Permission given to a user, program, or process to access an object or set of objects. In Oracle Database, authorization is done through the role mechanism. A single person or a group of people can be granted a role or a group of roles. A role, in turn, can be granted other roles.

●　backup

A representative copy of data. This copy includes important parts of your database such as control files, redo log files, and datafiles.

A backup is a safeguard against unexpected data loss; if you lose your original data, then you can use the backup to make the data available again. A backup is also a safeguard against an application error; if an application makes incorrect changes, then you can restore the backup.

●　certificate authority

A certificate authority (CA) is a trusted third party that certifies the identity of other entities such as users, databases, administrators, clients, and servers. The certificate authority verifies the user's identity and grants a certificate, signing it with one of the certificate authority's private keys.

●　COM

Microsoft's Component Object Model is an object-oriented programming architecture and a set of operating system services. These services notify application components of significant events and ensure that they are authorized to run. COM is intended to make it relatively easy to create business applications that work well with Microsoft Transaction Server.

●　component-based shadow copies

VSS snapshots of Oracle database components. Examples of components include tablespaces or archived redo logs.

●　connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination services and network route information. The destination service is indicated by using its service name for Oracle9i or Oracle8i databases or its Oracle system identifier for Oracle8 Release 8.0 databases. The network route provides, at a minimum, the location of the listener through use of a network address.

●　connect identifier

A net service name or service name, that maps to a connect descriptor. Users initiate a connect request by passing a username and password along with a connect identifier in a connect string for the services to which they want to connect, for example:

CONNECT username/password@connect_identifier

●　connect string

See net service name.

●　control files

Files that record the physical structure of a database and contain the database name, the names and locations of associated databases and online redo log files, the time stamp of the database creation, the current log sequence number, and checkpoint information.

●　credentials

A username, password, or certificate used to gain access to the database.

●　data dictionary

A set of read-only tables that provide information about a database.

●　database alias

See net service name.

●　decryption

Process of converting contents of a message that has gone through encryption (ciphertext) back into its original readable format (plaintext).

●　digital certificates

ITU X.509 v3 standard data structures that securely bind an identity to a public key. A certificate is created when an entity's public key is signed by a trusted identity, a certificate authority. The certificate ensures that the entity's information is correct and that the public key actually belongs to that entity.

●　digital signature

Digital signatures are created when a public key algorithm is used to sign messages with senders' private keys. A digital signature assures that a document is authentic, has not been forged by another entity, has not been altered, and cannot be repudiated by the sender.

●　DLL

See dynamic link library.

●　downgrade

To convert the data in Oracle Database to an earlier Oracle release. See upgrade and migrate.

●　dynamic link library

An executable file that a Windows application can load when needed.

●　encryption

Process of disguising a message, rendering it unreadable to any but the intended recipient.

●　enterprise domains

Directory constructs consisting of Oracle Database and enterprise users and roles.

●　enterprise role

A directory structure which contains global roles on multiple databases, and which can be granted to an enterprise user.

●　enterprise user

A user that has a unique identity across an enterprise. An enterprise user connects to individual databases through a schema and is assigned an enterprise role that determines the user's access privileges on databases.

●　external procedures

Functions written in a third-generation language (C, for example) and callable from within PL/SQL or SQL as if they were PL/SQL functions or procedures.

●　external role

Roles created and managed by Windows operating systems. Once an external role is created, you can grant or revoke that role to a database user. You must set init.ora parameter OS_ROLES to true and restart Oracle Database before you can create an external role. You cannot use both Windows operating systems and Oracle Database to grant roles concurrently.

●　external routine

A function written in a third-generation language (3GL), such as C, and callable from within PL/SQL or SQL as if it were a PL/SQL function or procedure.

●　external user

A user authenticated by the Windows operating system who can access Oracle Database without being prompted for a password. External users are typically regular database users (non-database administrators) to which you assign standard database roles (such as DBA), but do not want to assign SYSDBA (database administrator) or SYSOPER (database operator) privilege.

●　external user

The Windows operating system can authenticate a user, who can then access Oracle Database without being prompted for a password. External users are typically regular database users (non-database administrators) to whom you assign standard database roles (such as DBA), but do not want to assign the SYSDBA (database administrator) or SYSOPER (database operator) privilege.

●　global groups

See Windows global groups.

●　global role

A role whose privileges are contained within a single database, but which is managed in a directory.

●　Globalization Support

The Oracle Database architecture that ensures that database utilities, error messages, sort order, date, time, monetary, numeric, and calendar conventions automatically adapt to the native language and locale.

●　HOME_NAME

Represents the name of an Oracle home. In Oracle Database 11g Release 2 (11.2), all Oracle homes have a unique HOME_NAME.

●　init.ora

See initialization parameter file.

●　initialization parameter file

An ASCII text file that contains information needed to initialize a database and instance.

●　instance

Every Oracle Database is associated with an Oracle Database or Automatic Storage Management instance. When a database is started on a database server (regardless of the type of computer), Oracle Database allocates a memory area called the System Global Area and starts one or more Oracle Database processes. This combination of the System Global Area and Oracle Database processes is called an instance. The memory and processes of an instance manage the associated database's data efficiently and serve the users of the database.

●　instantiate

Produce a more defined version of some object by replacing variables with values (or other variables).

●　latch

A simple, low-level serialization mechanism to protect shared data structures in the System Global Area.

●　LDAP

See Lightweight Directory Access Protocol (LDAP).

●　Lightweight Directory Access Protocol (LDAP)

A standard, extensible directory access protocol. It is a common language that LDAP clients and servers use to communicate. LDAP is a framework of design conventions supporting industry-standard directory products, such as Oracle Internet Directory.

●　listener

The Oracle Database server process that listens for and accepts incoming connection requests from client applications. The listener process starts Oracle Database processes to handle subsequent communications with the client; then it goes back to listening for new connection requests.

●　listener.ora

A configuration file that describes one or more Transparent Network Substrate (TNS) listeners on a server.

●　local groups

See Windows local groups.

●　local roles

Roles created and managed by the database. Once a local role is created, you can grant or revoke that role to a database user. You cannot use Windows (for external role management) and Oracle Database (for local role management) concurrently.

●　Microsoft Management Console

An application that serves as a host for administrative tools called snap-ins. By itself, Microsoft Management Console does not provide any functionality.

●　Microsoft Transaction Server

A transaction processing system based on COM that runs on an Internet or network server.

●　migrate

To upgrade or downgrade an Oracle Database or convert the data in a non-Oracle database into an Oracle Database.

●　mount

To associate a database with an instance that has been started.

●　MTS

See Microsoft Transaction Server

●　multiple Oracle homes

The capability of having multiple Oracle home on a computer.

●　net service name

The name used by clients to identify an Oracle Net server and the specific system identifier or database for the Oracle Net connection. A net service name is mapped to a port number and protocol. Also known as a connect string, database alias, host string, or service name.

This also identifies the specific system identifier or database to which the connection is attaching, not just the Oracle Net server.

●　network listener

A listener on a server that listens for connection requests for one or more databases on one or more protocols. See listener.

●　network service

In an Oracle application network, a service performs tasks for its service consumers. For example, a Names Server provides name resolution services for clients.

●　obfuscated

Protected by a process often used by companies for intellectual property written in the form of Java programs. The obfuscation process mixes up Java symbols found in the code. It leaves the original program structure intact, allowing the program to run correctly, while changing the names of the classes, methods, and variables to hide the intended behavior. Although it is possible to decompile and read non-obfuscated Java code, obfuscated Java code is sufficiently difficult to decompile to satisfy U.S. government export controls.

●　OCI

See Oracle Call Interface.

●　OFA

See Optimal Flexible Architecture.

●　Optimal Flexible Architecture

A set of file naming and placement guidelines for Oracle Database software and databases.

●　ORACLE_BASE

ORACLE_BASE is the root of the Oracle Database directory tree. If you install an OFA-compliant database using Oracle Universal Installer defaults, then ORACLE_BASE is X:\app\oracle\product\11.2.0 where X is any hard drive.

●　Oracle Call Interface

An application programming interface that enables you to manipulate data and schema in an Oracle Database. You compile and link an Oracle Call Interface application in the same way that you compile and link a non-database application. There is no need for a separate preprocessing or precompilation step.

●　ORACLE_HOME

Corresponds to the environment in which Oracle Database products run. This environment includes the location of installed product files, the PATH variable pointing to the binary files of installed products, registry entries, net service names, and program groups.

If you install an OFA-compliant database, using Oracle Universal Installer defaults, then Oracle home (known as ORACLE_HOME in this guide) is located beneath ORACLE_BASE. It contains subdirectories for Oracle Database software executables and network files.

●　Oracle Internet Directory

An Oracle Database-based LDAP V3 directory server, used for centralizing database user, Oracle Net network connector, and database listener parameters. Oracle Internet Directory ships only with Oracle Application Server, not the Oracle Database 11g product set.

●　Oracle Net

A component of Oracle Net Services that enables a network session from a client application to an Oracle Database server. Once a network session is established, Oracle Net acts as a data courier for the client application and the database server. It is responsible for establishing and maintaining the connection between the client application and database server, and exchanging messages between them. Oracle Net can perform these jobs because it is located on each computer in the network.

●　Oracle Net Services

A suite of networking components that provide enterprise-wide connectivity solutions in distributed, heterogeneous computing environments. Oracle Net Services are comprised of Oracle Net, listener, Oracle Connection Manager, Oracle Net Configuration Assistant, and Oracle Net Manager.

●　Oracle PKI

Oracle Advanced Security includes Oracle PKI (public key infrastructure) integration for authentication and single sign-on. Oracle-based applications are integrated with the PKI authentication and encryption framework, using Oracle Wallet Manager.

●　Oracle Protocol Support

A product that maps the functions of a given network protocol into Oracle Transparent Network Substrate (TNS) architecture. This process translates TNS function calls into requests to the underlying network protocol. This allows TNS to act as an interface among all protocols. Oracle Net requires Oracle Protocol Support.

●　Oracle services

Windows services that are associated with particular Oracle Database components.

●　Oracle VSS writer

A service on Windows systems that acts as coordinator between an Oracle database instance and other VSS components, enabling data providers to create a shadow copy of files managed by the Oracle instance. For example, the Oracle VSS writer can place datafiles in hot backup mode to provide a recoverable copy of these datafiles in a shadow copy set.

●　PL/SQL

Procedural language extension to SQL that is part of Oracle Database.

PL/SQL enables you to mix SQL statements with procedural constructs. You can define and run PL/SQL program units such as procedures, functions, and packages.

●　precompiler

A programming tool that enables you to embed SQL statements in a high-level source program.

●　private keys

In public key cryptography, these are the secret keys. They are used primarily for decryption but also for encryption with a digital signature.

●　privilege

A right to run a particular type of SQL statement or to access another user's object.

●　process

A mechanism in an operating system that can run an executable. (Some operating systems use the terms job or task.) A process normally has its own private memory area in which it runs. On Windows a process is created when an application runs (such as Oracle Database or Microsoft Word). In addition to an executable program, all processes consist of at least one thread. The Oracle Database master process contains hundreds of threads.

●　provider

Software or hardware that creates shadow copies on demand. Typically, a provider is a disk storage system. In response to a request from a requester, a provider responds to VSS COM messages to create and maintain shadow copies.

●　public key

In public key cryptography, this key is made public to all. It is primarily used for encryption but can also be used for verifying signatures.

●　public key cryptography

Public key cryptography involves information encryption and decryption using a shared public key paired with private keys. Provides for secure, private communications within a public network.

●　quota

A limit on a resource, such as a limit on the amount of database storage used by a database user. A database administrator can set tablespace quotas for each Oracle Database username.

●　raw partitions

Portions of a physical disk that are accessed at the lowest possible disk (block) level.

●　recovery

To restore a physical backup is to reconstruct it and make it available to the Oracle Database server. To recover a restored backup is to update it using redo records (that is, records of changes made to the database after the backup was taken). Recovering a backup involves two distinct operations: rolling forward the backup to a more current time by applying redo data, and rolling back all changes made in uncommitted transactions to their original state.

●　redo log buffer

A circular buffer in the System Global Area that contains information about changes made to the database.

●　redo log files

Files that contain a record of all changes made to data in the database buffer cache. If an instance failure occurs, then the redo log files are used to recover the modified data that was in memory.

●　registry

A Windows repository that stores configuration information for a computer.

●　remote computer

A computer on a network other than the local computer.

●　remote database

A database on a computer other than the local database.

●　requester

An application that uses the VSS API to create shadow copies. Requester applications communicate with VSS writers to gather information on the system and to signal writers to prepare data for backup. The requester maintain control over VSS backup and restore operations by generating COM events through calls in the VSS API.

●　replication

The process of copying and maintaining database objects in multiple databases that make up a distributed database system.

●　role

A named groups of related privileges. You can grant a role to users or to another role.

●　schema

A named collection of objects, such as tables, views, clusters, procedures, and packages, associated with one or more particular users.

●　services

Executable processes installed in the Windows registry and administered by Windows. Once services are created and started, they can run even when no user is logged on to the computer.

●　service name

See net service name.

●　SGA

See System Global Area.

●　shadow copy

A consistent snapshot of a component or volume.

●　shadow copy set

A collection of shadow copies that are all taken at the same time.

●　Shared Server Process

A server configuration which allows many user processes to share very few server processes. The user processes connect to a dispatcher background process, which routes client requests to the next available shared server process.

●　SID

See system identifier.

●　snap-ins

Administrative tools that run within Microsoft Management Console.

●　snapshot

(1) Information stored in rollback segments provide transaction recovery and read consistency. Use Rollback segment information to re-create a snapshot of a row before an update.

(2) A point-in-time copy of a master table located on a remote site. Read-only snapshots can be queried, but not updated. Updateable snapshots can be queried and updated. They are periodically refreshed to reflect changes made to the master table, and at the snapshot site.

●　starter database

A preconfigured, ready-to-use database that requires minimal user input to create.

●　SYSDBA

A special database administration role that contains all system privileges with the ADMIN OPTION, and the SYSOPER system privilege. SYSDBA also permits CREATE DATABASE actions and time-based recovery.

●　SYSOPER

A special database administration role that permits a database administrator to perform STARTUP, SHUTDOWN, ALTER DATABASE OPEN/MOUNT, ALTER DATABASE BACKUP, ARCHIVE LOG, and RECOVER, and includes the RESTRICTED SESSION privilege.

●　System Global Area

A group of shared memory structures that contain data and control information for an Oracle Database instance.

●　system identifier

A unique name for an Oracle Database instance. To switch between instances of Oracle Database, users must specify the desired system identifier. The system identifier is included in the CONNECT DATA parts of the connect descriptors in a tnsnames.ora file, and in the definition of the network listener in a tnsnames.ora file.

●　SYSTEM

One of two standard database administrator usernames automatically created with each database. (The other user name is SYS.). The SYSTEM user name is the preferred user name for database administrators to use for database maintenance.

●　tablespace

A database is divided into one or more logical storage units called tablespaces. Tablespaces are divided into logical units of storage called segments, which are further divided into extents.

●　thread

An individual path of execution within a process. Threads are objects within a process that run program instructions. Threads allow concurrent operations within a process so that a process can run different parts of its program simultaneously on different processors. A thread is the most fundamental component that can be scheduled on Windows.

●　tnsnames.ora

A file that contains connect descriptors mapped to net service names. The file can be maintained centrally or locally, for use by all or individual clients.

●　trace file

Each server and background process can write to an associated trace file. When a process detects an internal error, it dumps information about the error to its trace file. Some information written to a trace file is intended for the database administrator, while other information is intended for Oracle Support Services. Trace file information is also used to tune applications and instances.

●　trust points

Trust points or trusted certificates are third party identities that are qualified with a level of trust. A trusted certificate is used when an identity is being validated as the entity it claims to be. Certificate authorities you trust are called trusted certificates. If there are several levels of trusted certificates, a trusted certificate at a lower level in the certificate chain does not need to have all its higher level certificates reverified.

●　universal groups

Universal groups are available in Windows. They can contain other groups, including other universal groups, local groups, and global groups.

●　upgrade

To convert the data in an Oracle Database into a later release. See downgrade and migrate.

●　username

A name that can connect to and access objects in a database.

●　view

A selective presentation of the structure and data of one or more tables. Views can also be based on other views.

●　volume-based shadow copies

VSS snapshots of complete drives or volumes.

●　Volume Shadow Copy Service (VSS)

An infrastructure on Windows server platforms that enables requesters, writers and providers to participate in creation of consistent snapshots called Shadow Copies. The VSS service uses well-defined COM interfaces.

●　Windows global groups

Groups that can be granted permissions and rights in their own domain, member servers and workstations of their domain, and in trusted domains. They can also become members of Windows local groups in all these places. But global groups can contain user accounts only from their own domains.

●　Windows local groups

Groups that can be granted permissions and rights only for its own computer or, if part of a domain, to the domain controllers of that domain. Local groups can, however, contain user accounts and Windows global groups from both their own domain and from trusted domains

●　writer

An application or service that stores persistent information on disk and cooperates with providers and requesters within the VSS infrastructure.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　application context

A name-value pair that enables an application to access session information about a user, such as the user ID or other user-specific information, and then securely pass this data to the database.

See also application role.

●　separation of duty

Restricting activities only to those users who must perform them. For example, you should not grant the SYSDBA privilege to any user. Only grant this privilege to administrative users. Separation of duty is required by many compliance policies. See "Guidelines for Securing User Accounts and Privileges" for guidelines on granting privileges to the correct users.

●　service ticket

See Kerberos ticket.

●　wallet

A data structure used to store and manage security credentials for an individual entity.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　.odbc.ini file

See "ODBC initialization file (ODBC INI)".

●　ACID transaction semantics

An acronym referring to the four fundamental properties of a transaction: atomicity, consistency, isolation and durability.

●　atomicity

A property of a transaction whereby either all or none of the operations of a transaction are applied to the database.

●　backup instance

A set of files containing backup information for a given database, residing at a given backup path. See also "backup path", "full backup" and "incremental backup".

●　backup path

The location of a database, specified by a directory name and an optional basename.

●　backup point

The time at which a backup begins. See also "backup path", "full backup" and "incremental backup".

●　bitmap index

Indexes are used to speed up queries on a table. Bitmap indexes are useful when searching and retrieving data from columns with low cardinality. That is, these columns can have only a few unique possible values.

●　cache group

A set of cached tables related through foreign keys.

●　cache instance

A set of rows related through foreign keys. Each cache instance contains exactly one row from the root table of a cache group and zero or more rows from the other tables in the cache group.

●　client/server

An approach to application design and development in which application processing is divided between components running on an end user's machine, such as the client, and a network server. Generally, user interface elements are implemented in the client component, while the server controls database access.

●　client data source name

See "data source name, client".

●　concurrency

The ability to have multiple transactions access and manipulate the database at the same time.

●　connection

A data path between an application and a particular ODBC data source.

●　connection attribute

A character string that defines a connection parameter to be used when connecting to an ODBC data source. Connection attributes have the form name=value, where name is the name of the parameter and value is the parameter value. See also connection string.

●　connection request

A message sent by an application through an ODBC driver to an ODBC data source to request a connection to that data source.

●　connection string

A character string that defines the connection parameters to be used when connecting to an ODBC data source. A connection string is expressed as one or more connection attributes separated by semicolons.

●　consistency

A property of transactions whereby each transaction transforms the database from one consistent state to another.

●　cursor

A control structure used by an application to iterate through the results of an SQL query.

●　data source definition

A named collection of connection attributes that defines the connection parameters to be used when connecting to an ODBC data source. See also "data source name".

●　data source name

A logical name by which an end user or application refers to an ODBC data source definition. Sometimes incorrectly used to mean "data source definition". See also "data source definition", ODBC.INI file.

●　data source name, client

A data source name defined on a TimesTen client machine that refers to a Server DSN on a server machine.

●　data source name, server

A system data source name (system DSN) defined on a server machine. Server Data Source Names become available to all TimesTen clients on a network when the TimesTen Server is running.

●　data source name, system

A data source name that is accessible by all users of a particular machine.

●　data source name, user

A data source name that is accessible only by the user who created the data source name.

●　driver

See "ODBC driver".

●　DSN

See "data source name".

●　DSN, client

See "data source name, client".

●　DSN, server

See "data source name, server".

●　DSN, system

See "data source name, system".

●　DSN, user

See "data source name, user".

●　durability

A property of transactions whereby the effects of a committed transaction survive system failures.

●　environment variable

A name, value pair maintained by the operating system that can be used to pass configuration parameters to an application.

●　event

An activity or occurrence that can be tracked by a logging mechanism in an application, service or operating system. See also "logging", "protocol message logging" and "event viewer".

●　event viewer

On Windows, a utility program used to view the contents of the operating system event log.

●　full backup

A database backup procedure in which a complete copy of a database is created. Typically, the first backup of a database must be a full backup. See also "incremental backup".

●　hash index

Indexes are used to speed up queries on a table. Hash indexes are useful for finding rows with an exact match on one or more columns.

●　host

A computer. Typically used to refer to a computer on a network that provides services to other computers on the network.

●　host name

A character string name that uniquely identifies a particular computer on a network. Examples: athena, thames.mycompany.com. See also "host".

●　in-line column

A column whose values are physically stored together with the other column values of a row.

●　incremental backup

A database backup procedure in which an existing backup is augmented with all the transaction log records created since its last full or incremental backup. See also "backup instance" and "full backup".

●　initialization file

See ODBC.INI file.

●　IP address

A numeric address that uniquely identifies a computer on a network and consists of four numbers separated by dots. Abbreviation for Internet Protocol address. Example: 123.61.129.91.

●　IPC

Inter Process Communication

●　isolation

A property of transactions whereby each transaction runs as if it were the only transaction in the system.

●　listener thread

A thread that runs on the TimesTen Server that receives and processes connection requests from TimesTen Clients.

●　logging

The process by which an application, service or operating system records specific events that occur during processing.

●　multithreading

A programming paradigm in which a process contains multiple threads of control.

●　network address

A host name, or IP address that uniquely identifies a particular computer on a network. Examples: 123.61.129.91, athena, thams.mycompany.com.

●　ODBC

See "Open Database Connectivity (ODBC)".

●　ODBC Administrator

A utility program used on Windows to create, configure and delete data source definitions.

●　ODBC data source

See "data source name" (DSN).

●　ODBC data source name

See "data source name" (DSN).

●　ODBC driver

A library that implements the function calls defined in the ODBC API and enables applications to interact with ODBC data sources.

●　ODBC Driver Manager

A library that acts as an intermediary between an ODBC application and one or more ODBC drivers.

●　ODBC initialization file (ODBC INI)

The ODBC.INI file contains a list of Data Sources and any properties for each. Each Data Source name must have a driver property defined. This enables the driver to be loaded when a connect call is made.

●　Open Database Connectivity (ODBC)

A database-independent application programming interface that enables applications to access data stored in heterogeneous relational and non-relational databases. Based on the Call-Level Interface (CLI) specification developed by X/Open's SQL Access Group and first popularized by Microsoft on the Windows platform.

Open database connectivity (ODBC), is a database access protocol that lets you connect to a database and then prepare and run SQL statements against the database. In conjunction with an ODBC driver, an application can access any data source including data stored in spreadsheets, like Excel. Because ODBC is a widely accepted standard API, applications can be written to comply to the ODBC standard. The ODBC driver performs all mappings between the ODBC standard and the particular database the application is accessing. Using a data source-specific driver, an ODBC compliant program can access any data source without any more development effort.

TimesTen provides the ODBC interface so that applications of any type that are ODBC compliant can access TimesTen using the ODBC driver provided by TimesTen.

●　out-of-line column

A column whose values are physically stored separately from the other column values of a row.

●　phantom

A row that appears during one read but not during another read within the same transaction, due to the actions of other concurrently executing transactions.

●　ping

A utility that tests the connection between two computers on a network by sending a message from one computer to the other and measuring how long it takes for the receiving system to confirm that the message was received. Typically packaged with network software.

●　port number

See "TCP/IP port number".

●　procedure

See "stored procedure".

●　process

An instance of a program in execution.

●　propagate

When using IMDB Cache to send table or row modifications from an IMDB Cache to an Oracle database. Compare with "replicate".

●　protocol message logging

The process that the TimesTen Server uses to record each message it receives through the TimesTen network protocol.

●　range index

Indexes are used to speed up queries on a table. A range index is similar in functionality to a B+-tree index and is best used for retrieving rows with column values within a certain range.

●　replicate

The sending of table or row modifications from one database to another. Compare with "propagate".

●　result set

A collection of zero or more rows of data that represent the result of an SQL query.

●　rollback

To undo the actions of a transaction, thereby returning all items modified by the transaction to their original state.

●　row buffering

A performance enhancement used by the TimesTen Client in which the client receives multiple result rows of an SQL query in each message from the TimesTen Server to reduce network communication.

●　RPC

Remote Procedure Call.

●　scalability

The degree to which a system or application can handle increasing demands on system resources without significant performance degradation.

●　schema

A schema is automatically created for a user upon user creation. A schema is the namespace for a given user, where all objects owned by this user belong and all objects are identified by schema qualified names. For example, user PAT belongs to the PAT schema. In addition, the object EMPLOYEES owned by PAT is identified as PAT.EMPLOYEES.

If a user refers to an object without the schema name, TimesTen first tries to resolve the name to the user's schema. If this object does not exist, TimesTen tries to resolve the name to SYS.EMPLOYEES.

A user always has all privileges to all objects in their own schema. These privileges can never be revoked.

●　server data source name

See "data source name, server".

●　server DSN

See "data source name, server".

●　system DSN

See "data source name, system".

●　shorthand name

A logical name used to refer to a particular TimesTen Server. Shorthand names relieve the end user of having to enter a host name and port number to connect to a TimesTen Server.

●　SMP

Symmetric multi-processing. A hardware configuration in which two or more similar processors are connected via a high-bandwidth link and managed by one operating system, where each processor has equal access to I/O devices.

●　SNMP

Simple Network Management Protocol. Used to manage nodes on a network.

●　SQL

Structured Query Language.

●　stack overflow condition

An error condition in which the stack usage of a thread or process exceeds the amount of space allocated for the stack.

●　stored procedure

An executable object or named entity stored in a database that can be invoked with input and output parameters and which can return result sets similar to those returned by an SQL query.

●　system account

A special account on Windows used by the operating system and certain operating system services. The TimesTen service and the TimesTen Server run under the system account.

●　system DSN

See "data source name, system".

●　TCP/IP

The communications protocol used by computers on the Internet. Abbreviation for Transport Control Protocol/Internet Protocol.

●　TCP/IP port number

A number used by TCP/IP that identifies the end point for a connection to a host that supports multiple simultaneous connections.

●　telnet

A utility program and protocol that enables a user on one computer to open a virtual terminal, log in to a remote host and interact as a terminal user of that host.

●　thread

An independent sequence of execution of program code inside a process. See also "process".

●　thread-safe ODBC driver

An ODBC driver that supports multithreaded servers and clients. The TimesTen data manager driver and the TimesTen Client driver are thread-safe.

●　timeout error

An error condition indicating that the requested operation did not complete within the given amount of time. See also "timeout interval".

●　timeout interval

A configuration parameter that specifies the maximum amount of time that an operation should take to complete. See also "timeout error".

●　TimesTen Client

(1) An ODBC driver that enables end users to access data sources through a TimesTen Server. (2) A computer on which the TimesTen Client software has been installed. Using the TimesTen Client driver, an end user or application can access any data source managed by an available TimesTen Server.

●　TimesTen Client/Server network protocol

The protocol used by TimesTen Clients and TimesTen Servers to exchange data over a standard TCP/IP network connection.

●　TimesTen Data Server

(1) An application program that makes TimesTen data sources available to the TimesTen Clients on a network. (2) A computer on which the TimesTen Data Server software is running.

●　TimesTen Server address

The host name or IP address used during installation of the TimesTen Server to identify the computer on which the software is being installed.

●　transaction

An operation or set of operations performed against data in a database. The operations defined in a transaction must be completed as a whole; if any part of the transaction fails, the entire transaction fails. See also "ACID transaction semantics".

●　UCS-4

A fixed-width, 32-bit Unicode character set. Each character occupies 32 bits of storage. The UCS-2 characters are the first 65,536 code points in this standard, so it can be viewed as a 32-bit extension of UCS-2.

●　UTF-16

An encoding scheme defined by the ISO/IEC 10646 standard in which each Unicode character is represented by either a two-byte integer or a pair of two-byte integers. Characters from European scripts and most Asian scripts are represented in two bytes. Surrogate pairs are represented in four bytes. Surrogate pairs represent characters such as infrequently used Asian characters that were not included in the original range of two-byte characters.

●　user account

The combination of a user name, password and access permissions that gives an individual user access to an operating system.

●　user data source name

See"data source name, user".

●　user DSN

See "data source name, user".

●　User Manager

A Windows utility program used to create user accounts and assign access rights and group membership.

●　Windows sockets (Winsock)

An API that defines a standard binary interface for TCP/IP transports on Windows platforms. This API adds Windows-specific extensions to the Berkeley Sockets interface originally defined in Berkeley UNIX.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　access control

The ability of a system to grant or limit access to specific data for specific clients or groups of clients.

●　Access Control Lists (ACLs)

The group of access directives that you define. The directives grant levels of access to specific data for specific clients, or groups of clients, or both.

●　Advanced Encryption Standard

Advanced Encryption Standard (AES) is a new cryptographic algorithm that has been approved by the National Institute of Standards and Technology as a replacement for DES. The AES standard is available in Federal Information Processing Standards Publication 197. The AES algorithm is a symmetric block cipher that can process data blocks of 128 bits, using cipher keys with lengths of 128, 192, and 256 bits.

●　AES

See Advanced Encryption Standard

●　attribute

An item of information that describes some aspect of an entry in an LDAP directory. An entry comprises a set of attributes, each of which belongs to an object class. Moreover, each attribute has both a type, which describes the kind of information in the attribute, and a value, which contains the actual data.

●　authentication

The process of verifying the identity of a user, device, or other entity in a computer system, often as a prerequisite to granting access to resources in a system. A recipient of an authenticated message can be certain of the message's origin (its sender). Authentication is presumed to preclude the possibility that another party has impersonated the sender.

●　authentication method

A security method that verifies a user's, client's, or server's identity in distributed environments. Network authentication methods can also provide the benefit of single sign-on (SSO) for users. The following authentication methods are supported in Oracle Database when Oracle Advanced Security is installed:

Kerberos
RADIUS
Secure Sockets Layer (SSL)
Windows native authentication

●　authorization

Permission given to a user, program, or process to access an object or set of objects. In Oracle, authorization is done through the role mechanism. A single person or a group of people can be granted a role or a group of roles. A role, in turn, can be granted other roles. The set of privileges available to an authenticated entity.

●　auto login wallet

An Oracle Wallet Manager feature that enables PKI- or password-based access to services without providing credentials at the time of access. This auto login access stays in effect until the auto login feature is disabled for that wallet. File system permissions provide the necessary security for auto login wallets. When auto login is enabled for a wallet, it is only available to the operating system user who created that wallet. Sometimes these are called "SSO wallets" because they provide single sign-on capability.

●　base

The root of a subtree search in an LDAP-compliant directory.

●　CA

See certificate authority

●　CDS

See Cell Directory Services (CDS)

●　Cell Directory Services (CDS)

An external naming method that enables users to use Oracle tools transparently and applications to access Oracle Database databases in a Distributed Computing Environment (DCE).

●　certificate

An ITU x.509 v3 standard data structure that securely binds an identify to a public key.

A certificate is created when an entity's public key is signed by a trusted identity, a certificate authority. The certificate ensures that the entity's information is correct and that the public key actually belongs to that entity.

●　certificate authority

A trusted third party that certifies that other entities—users, databases, administrators, clients, servers—are who they say they are. When it certifies a user, the certificate authority first seeks verification that the user is not on the certificate revocation list (CRL), then verifies the user's identity and grants a certificate, signing it with the certificate authority's private key. The certificate authority has its own certificate and public key which it publishes. Servers and clients use these to verify signatures the certificate authority has made. A certificate authority might be an external company that offers certificate services, or an internal organization such as a corporate MIS department.

●　certificate chain

An ordered list of certificates containing an end-user or subscriber certificate and its certificate authority certificates.

●　certificate request

A certificate request, which consists of three parts: certification request information, a signature algorithm identifier, and a digital signature on the certification request information. The certification request information consists of the subject's distinguished name, public key, and an optional set of attributes. The attributes may provide additional information about the subject identity, such as postal address, or a challenge password by which the subject entity may later request certificate revocation. See PKCS #10

●　certificate revocation lists

(CRLs) Signed data structures that contain a list of revoked certificates. The authenticity and integrity of the CRL is provided by a digital signature appended to it. Usually, the CRL signer is the same entity that signed the issued certificate.

●　checksumming

A mechanism that computes a value for a message packet, based on the data it contains, and passes it along with the data to authenticate that the data has not been tampered with. The recipient of the data recomputes the cryptographic checksum and compares it with the cryptographic checksum passed with the data; if they match, it is "probabilistic" proof the data was not tampered with during transmission.

●　Cipher Block Chaining (CBC)

An encryption method that protects against block replay attacks by making the encryption of a cipher block dependent on all blocks that precede it; it is designed to make unauthorized decryption incrementally more difficult. Oracle Advanced Security employs outer cipher block chaining because it is more secure than inner cipher block chaining, with no material performance penalty.

●　cipher suite

A set of authentication, encryption, and data integrity algorithms used for exchanging messages between network nodes. During an SSL handshake, for example, the two nodes negotiate to see which cipher suite they will use when transmitting messages back and forth.

●　cipher suite name

Cipher suites describe the kind of cryptographics protection that is used by connections in a particular session.

●　ciphertext

Message text that has been encrypted.

●　cleartext

Unencrypted plain text.

●　client

A client relies on a service. A client can sometimes be a user, sometimes a process acting on behalf of the user during a database link (sometimes called a proxy).

●　confidentiality

A function of cryptography. Confidentiality guarantees that only the intended recipient(s) of a message can view the message (decrypt the ciphertext).

●　connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination service and network route information. The destination service is indicated by using its service name for Oracle9i or Oracle8i databases or its Oracle system identifier (SID) for Oracle databases version 8.0. The network route provides, at a minimum, the location of the listener through use of a network address. See connect identifier

●　connect identifier

A connect descriptor or a name that maps to a connect descriptor. A connect identifier can be a net service name, database service name, or net service alias. Users initiate a connect request by passing a username and password along with a connect identifier in a connect string for the service to which they wish to connect:

CONNECT username@connect_identifier Enter password:

●　connect string

Information the user passes to a service to connect, such as username, password and net service name. For example:

CONNECT username@net_service_name

Enter password:

●　credentials

A username, password, or certificate used to gain access to the database.

●　CRL

See certificate revocation lists

●　CRL Distribution Point

(CRL DP) An optional extension specified by the X.509 version 3 certificate standard, which indicates the location of the Partitioned CRL where revocation information for a certificate is stored. Typically, the value in this extension is in the form of a URL. CRL DPs allow revocation information within a single certificate authority domain to be posted in multiple CRLs. CRL DPs subdivide revocation information into more manageable pieces to avoid proliferating voluminous CRLs, thereby providing performance benefits. For example, a CRL DP is specified in the certificate and can point to a file on a Web server from which that certificate's revocation information can be downloaded.

●　CRL DP

See CRL Distribution Point

●　cryptography

The practice of encoding and decoding data, resulting in secure messages.

●　data dictionary

A set of read-only tables that provide information about a database.

●　database administrator

(1) A person responsible for operating and maintaining an Oracle Server or a database application. (2) An Oracle username that has been given DBA privileges and can perform database administration functions. Usually the two meanings coincide. Many sites have multiple DBAs. (3) Members of the OracleDBAdmins directory administrative group, who manage the database user-schema mappings for a specific database entry in the directory. Database Configuration Assistant automatically adds the person who registers a database in the directory into the OracleDBAdmins group as the first member of this group for the database being registered.

●　database alias

See net service name

●　Database Installation Administrator

Also called a database creator. This administrator is in charge of creating new databases. This includes registering each database in the directory using the Database Configuration Assistant. This administrator has create and modify access to database service objects and attributes. This administrator can also modify the Default domain.

●　database link

A network object stored in the local database or in the network definition that identifies a remote database, a communication path to that database, and optionally, a username and password. Once defined, the database link is used to access the remote database.

A public or private database link from one database to another is created on the local database by a DBA or user.

A global database link is created automatically from each database to every other database in a network with Oracle Names. Global database links are stored in the network definition.

●　database method

See Oracle database method

●　database password verifier

A database password verifier is an irreversible value that is derived from the user's database password. This value is used during password authentication to the database to prove the identity of the connecting user.

●　Database Security Administrator

The highest level administrator for database enterprise user security. This administrator has permissions on all of the enterprise domains and is responsible for:

Administering the Oracle DBSecurityAdmins and OracleDBCreators groups.

Creating new enterprise domains.

Moving databases from one domain to another within the enterprise.

●　DCE

See Distributed Computing Environment (DCE)

●　decryption

The process of converting the contents of an encrypted message (ciphertext) back into its original readable format (plaintext).

●　dictionary attack

A common attack on passwords. the attacker creates a dictionary of many possible passwords and their corresponding verifiers. Through some means, the attacker then obtains the verifier corresponding to the target password, and obtains the target password by looking up the verifier in the dictionary.

●　Diffie-Hellman key negotiation algorithm

This is a method that lets two parties communicating over an insecure channel to agree upon a random number known only to them. Though the parties exchange information over the insecure channel during execution of the Diffie-Hellman key negotiation algorithm, it is computationally infeasible for an attacker to deduce the random number they agree upon by analyzing their network communications. Oracle Advanced Security uses the Diffie-Hellman key negotiation algorithm to generate session keys.

●　digital signature

A digital signature is created when a public key algorithm is used to sign the sender's message with the sender's private key. The digital signature assures that the document is authentic, has not been forged by another entity, has not been altered, and cannot be repudiated by the sender.

●　directory information tree (DIT)

A hierarchical tree-like structure consisting of the DNs of the entries in an LDAP directory. See distinguished name (DN)

●　directory naming

A naming method that resolves a database service, net service name, or net service alias to a connect descriptor stored in a central directory server. A

●　directory naming context

A subtree which is of significance within a directory server. It is usually the top of some organizational subtree. Some directories only permit one such context which is fixed; others permit none to many to be configured by the directory administrator.

●　Distributed Computing Environment (DCE)

A set of integrated network services that works across multiple systems to provide a distributed environment. The middleware between distributed applications and the operating system or network services; based on a client/server computing model. DCE is supported by the Open Group.

●　distinguished name (DN)

The unique name of a directory entry. It is comprised of all of the individual names of the parent entries back to the root entry of the directory information tree. See directory information tree (DIT)

●　domain

Any tree or subtree within the Domain Name System (DNS) namespace. Domain most commonly refers to a group of computers whose host names share a common suffix, the domain name.

●　Domain Name System (DNS)

A system for naming computers and network services that is organized into a hierarchy of domains. DNS is used in TCP/IP networks to locate computers through user-friendly names. DNS resolves a friendly name into an IP address, which is understood by computers.

In Oracle Net Services, DNS translates the host name in a TCP/IP address into an IP address.

●　encrypted text

Text that has been encrypted, using an encryption algorithm; the output stream of an encryption process. On its face, it is not readable or decipherable, without first being subject to decryption. Also called ciphertext. Encrypted text ultimately originates as plaintext.

●　encryption

The process of disguising a message rendering it unreadable to any but the intended recipient.

●　enterprise domain

A directory construct that consists of a group of databases and enterprise roles. A database should only exist in one enterprise domain at any time. Enterprise domains are different from Windows 2000 domains, which are collections of computers that share a common directory database.

●　enterprise domain administrator

User authorized to manage a specific enterprise domain, including the authority to add new enterprise domain administrators.

●　enterprise role

Access privileges assigned to enterprise users. A set of Oracle role-based authorizations across one or more databases in an enterprise domain. Enterprise roles are stored in the directory and contain one or more global roles.

●　enterprise user

A user defined and managed in a directory. Each enterprise user has a unique identity across an enterprise.

●　entry

The building block of a directory, it contains information about an object of interest to directory users.

●　external authentication

Verification of a user identity by a third party authentication service, such as Kerberos or RADIUS.

●　file system method

Storing fingerprint templates in files when configuring Identix Biometric authentication. The alternative is to use the Oracle database method.

●　Federal Information Processing Standard (FIPS)

A U.S. government standard that defines security requirements for cryptographic modules—employed within a security system protecting unclassified information within computer and telecommunication systems. Published by the National Institute of Standards and Technology (NIST).

●　FIPS

See Federal Information Processing Standard (FIPS)

●　forest

A group of one or more Active Directory trees that trust each other. All trees in a forest share a common schema, configuration, and global catalog. When a forest contains multiple trees, the trees do not form a contiguous namespace. All trees in a given forest trust each other through transitive bidirectional trust relationships.

●　forwardable ticket-granting ticket

In Kerberos. A service ticket with the FORWARDABLE flag set. This flag enables authentication forwarding without requiring the user to enter a password again.

●　GDS

See Global Directory Service (GDS)

●　Global Directory Service (GDS)

GDS is the DCE directory service that acts as an agent between DCE CDS and any X.500 directory service. Both GDS and CDS are obsolete; they are only used by DCE.

●　global role

A role managed in a directory, but its privileges are contained within a single database. A global role is created in a database by using the following syntax:

CREATE ROLE <role_name> IDENTIFIED GLOBALLY;

●　grid computing

A computing architecture that coordinates large numbers of servers and storage to act as a single large computer. Oracle Grid Computing creates a flexible, on-demand computing resource for all enterprise computing needs. Applications running on the Oracle 10g, or later, grid computing infrastructure can take advantage of common infrastructure services for failover, software provisioning, and management. Oracle Grid Computing analyzes demand for resources and adjusts supply accordingly.

●　HTTP

Hypertext Transfer Protocol: The set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Relative to the TCP/IP suite of protocols (which are the basis for information exchange on the Internet), HTTP is an application protocol.

●　HTTPS

The use of Secure Sockets Layer (SSL) as a sublayer under the regular HTTP application layer.

●　identity

The combination of the public key and any other public information for an entity. The public information may include user identification data such as, for example, an e-mail address. A user certified as being the entity it claims to be.

●　identity management

The creation, management, and use of online, or digital, entities. Identity management involves securely managing the full life cycle of a digital identity from creation (provisioning of digital identities) to maintenance (enforcing organizational policies regarding access to electronic resources), and, finally, to termination.

●　identity management realm

A subtree in Oracle Internet Directory, including not only an Oracle Context, but also additional subtrees for users and groups, each of which are protected with access control lists.

●　initial ticket

In Kerberos authentication, an initial ticket or ticket granting ticket (TGT) identifies the user as having the right to ask for additional service tickets. No tickets can be obtained without an initial ticket. An initial ticket is retrieved by running the okinit program and providing a password.

●　instance

Every running Oracle database is associated with an Oracle instance. When a database is started on a database server (regardless of the type of computer), Oracle allocates a memory area called the System Global Area (SGA) and starts an Oracle process. This combination of the SGA and an Oracle process is called an instance. The memory and the process of an instance manage the associated database's data efficiently and serve the one or more users of the database.

●　integrity

The guarantee that the contents of the message received were not altered from the contents of the original message sent.

●　java code obfuscation

Java code obfuscation is used to protect Java programs from reverse engineering. A special program (an obfuscator) is used to scramble Java symbols found in the code. The process leaves the original program structure intact, letting the program run correctly while changing the names of the classes, methods, and variables in order to hide the intended behavior. Although it is possible to decompile and read non-obfuscated Java code, the obfuscated Java code is sufficiently difficult to decompile to satisfy U.S. government export controls.

●　Java Database Connectivity (JDBC)

An industry-standard Java interface for connecting to a relational database from a Java program, defined by Sun Microsystems.

●　JDBC

See Java Database Connectivity (JDBC)

●　KDC

Key Distribution Center. In Kerberos authentication, the KDC maintains a list of user principals and is contacted through the kinit (okinit is the Oracle version) program for the user's initial ticket. Frequently, the KDC and the Ticket Granting Service are combined into the same entity and are simply referred to as the KDC. The Ticket Granting Service maintains a list of service principals and is contacted when a user wants to authenticate to a server providing such a service. The KDC is a trusted third party that must run on a secure host. It creates ticket-granting tickets and service tickets.

●　Kerberos

A network authentication service developed under Massachusetts Institute of Technology's Project Athena that strengthens security in distributed environments. Kerberos is a trusted third-party authentication system that relies on shared secrets and assumes that the third party is secure. It provides single sign-on capabilities and database link authentication (MIT Kerberos only) for users, provides centralized password storage, and enhances PC security.

●　key

When encrypting data, a key is a value which determines the ciphertext that a given algorithm will produce from given plaintext. When decrypting data, a key is a value required to correctly decrypt a ciphertext. A ciphertext is decrypted correctly only if the correct key is supplied.

With a symmetric encryption algorithm, the same key is used for both encryption and decryption of the same data. With an asymmetric encryption algorithm (also called a public-key encryption algorithm or public-key cryptosystem), different keys are used for encryption and decryption of the same data.

●　key pair

A public key and its associated private key. See public and private key pair

●　keytab file

A Kerberos key table file containing one or more service keys. Hosts or services use keytab files in the same way as users use their passwords.

●　kinstance

An instantiation or location of a Kerberos authenticated service. This is an arbitrary string, but the host computer name for a service is typically specified.

●　kservice

An arbitrary name of a Kerberos service object.

●　LDAP

See Lightweight Directory Access Protocol (LDAP)

●　ldap.ora file

A file created by Oracle Net Configuration Assistant that contains the following directory server access information:

Type of directory server
Location of the directory server
Default identity management realm or Oracle Context (including ports) that the client or server will use

●　Lightweight Directory Access Protocol (LDAP)

A standard, extensible directory access protocol. It is a common language that LDAP clients and servers use to communicate. The framework of design conventions supporting industry-standard directory products, such as the Oracle Internet Directory.

●　listener

A process that resides on the server whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

Every time a client requests a network session with a server, a listener receives the actual request. If the client information matches the listener information, then the listener grants a connection to the server.

●　listener.ora file

A configuration file for the listener that identifies the:

Listener name
Protocol addresses that it is accepting connection requests on
Services it is listening for

The listener.ora file typically resides in $ORACLE_HOME/network/admin on UNIX platforms and ORACLE_BASE\ORACLE_HOME\network\admin on Windows.

●　man-in-the-middle

A security attack characterized by the third-party, surreptitious interception of a message, wherein the third-party, the man-in-the-middle, decrypts the message, re-encrypts it (with or without alteration of the original message), and re-transmits it to the originally-intended recipient—all without the knowledge of the legitimate sender and receiver. This type of security attack works only in the absence of authentication.

●　message authentication code

Also known as data authentication code (DAC). A checksumming with the addition of a secret key. Only someone with the key can verify the cryptographic checksum.

●　message digest

See checksumming

●　naming method

The resolution method used by a client application to resolve a connect identifier to a connect descriptor when attempting to connect to a database service.

●　National Institute of Standards and Technology (NIST)

An agency within the U.S. Department of Commerce responsible for the development of security standards related to the design, acquisition, and implementation of cryptographic-based security systems within computer and telecommunication systems, operated by a Federal agency or by a contractor of a Federal agency or other organization that processes information on behalf of the Federal Government to accomplish a Federal function.

●　net service alias

An alternative name for a directory naming object in a directory server. A directory server stores net service aliases for any defined net service name or database service. A net service alias entry does not have connect descriptor information. Instead, it only references the location of the object for which it is an alias. When a client requests a directory lookup of a net service alias, the directory determines that the entry is a net service alias and completes the lookup as if it was actually the entry it is referencing.

●　net service name

The name used by clients to identify a database server. A net service name is mapped to a port number and protocol. Also known as a connect string, or database alias.

●　network authentication service

A means for authenticating clients to servers, servers to servers, and users to both clients and servers in distributed environments. A network authentication service is a repository for storing information about users and the services on different servers to which they have access, as well as information about clients and servers on the network. An authentication server can be a physically separate computer, or it can be a facility co-located on another server within the system. To ensure availability, some authentication services may be replicated to avoid a single point of failure.

●　network listener

A listener on a server that listens for connection requests for one or more databases on one or more protocols. See listener

●　NIST

See Federal Information Processing Standard (FIPS)

●　non-repudiation

Incontestable proof of the origin, delivery, submission, or transmission of a message.

●　obfuscation

A process by which information is scrambled into a non-readable form, such that it is extremely difficult to de-scramble if the algorithm used for scrambling is not known.

●　obfuscator

A special program used to obfuscate Java source code. See obfuscation

●　object class

A named group of attributes. When you want to assign attributes to an entry, you do so by assigning to that entry the object classes that hold those attributes. All objects associated with the same object class share the same attributes.

●　Oracle Context

1. An entry in an LDAP-compliant internet directory called cn=OracleContext, under which all Oracle software relevant information is kept, including entries for Oracle Net Services directory naming and checksumming security.

There can be one or more Oracle Contexts in a directory. An Oracle Context is usually located in an identity management realm.

●　OracleContextAdmins

An administrative group in Oracle Internet Directory whose members have full access to all groups and entries within its associated realm Oracle Context.

●　Oracle database method

Using an Oracle database to store fingerprint templates when configuring Indentix Biometric authentication. The alternative is to use the file system method.

●　OracleDBAdmins

An administrative group in Oracle Internet Directory whose members manage the database user-schema mappings for a particular database that is registered in the directory.

●　OracleDBCreators

An administrative group in Oracle Internet Directory whose members create new databases and registers them in the directory by using Database Configuration Assistant.

●　OracleDBSecurityAdmins

An administrative group in Oracle Internet Directory whose members have permissions on all of the enterprise domains to configure the identity management realm for enterprise users.

●　Oracle Net Services

An Oracle product that enables two or more computers that run the Oracle server or Oracle tools such as Designer/2000 to exchange data through a third-party network. Oracle Net Services support distributed processing and distributed database capability. Oracle Net Services is an open system because it is independent of the communication protocol, and users can interface Oracle Net to many network environments.

●　OraclePasswordAccessibleDomains

See Password-Accessible Domains List

●　Oracle PKI certificate usages

Defines Oracle application types that a certificate supports.

●　OracleUserSecurityAdmins

An administrative group in Oracle Internet Directory whose members can administer Oracle database users' security in the directory.

●　Password-Accessible Domains List

A group of enterprise domains configured to accept connections from password-authenticated users.

●　PCMCIA cards

Small credit card-sized computing devices that comply with the Personal Computer Memory Card International Association (PCMCIA) standard. These devices, also called PC cards, are used for adding memory, modems, or as hardware security modules. PCMCIA cards used as hardware security modules securely store the private key component of a public and private key pair and some also perform the cryptographic operations as well.

●　peer identity

SSL connect sessions are between a particular client and a particular server. The identity of the peer may have been established as part of session setup. Peers are identified by X.509 certificate chains.

●　PEM

The Internet Privacy-Enhanced Mail protocols standard, adopted by the Internet Architecture Board to provide secure electronic mail over the Internet. The PEM protocols provide for encryption, authentication, message integrity, and key management. PEM is an inclusive standard, intended to be compatible with a wide range of key-management approaches, including both symmetric and public-key schemes to encrypt data-encrypting keys. The specifications for PEM come from four Internet Engineering Task Force (IETF) documents: RFCs 1421, 1422, 1423, and 1424.

●　PKCS #10

An RSA Security, Inc., Public-Key Cryptography Standards (PKCS) specification that describes a syntax for certification requests. A certification request consists of a distinguished name, a public key, and optionally a set of attributes, collectively signed by the entity requesting certification. Certification requests are referred to as certificate requests in this manual. See certificate request

●　PKCS #11

An RSA Security, Inc., Public-Key Cryptography Standards (PKCS) specification that defines an application programming interface (API), called Cryptoki, to devices which hold cryptographic information and perform cryptographic operations. See PCMCIA cards

●　PKCS #12

An RSA Security, Inc., Public-Key Cryptography Standards (PKCS) specification that describes a transfer syntax for storing and transferring personal authentication credentials—typically in a format called a wallet.

●　PKI

See public key infrastructure (PKI)

●　plaintext

Message text that has not been encrypted.

●　principal

A string that uniquely identifies a client or server to which a set of Kerberos credentials is assigned. It generally has three parts: kservice/kinstance@REALM. In the case of a user, kservice is the username. See also kservice, kinstance, and realm

●　private key

In public-key cryptography, this key is the secret key. It is primarily used for decryption but is also used for encryption with digital signatures. See public and private key pair

●　proxy authentication

A process typically employed in an environment with a middle tier such as a firewall, wherein the end user authenticates to the middle tier, which then authenticates to the directory on the user's behalf—as its proxy. The middle tier logs into the directory as a proxy user. A proxy user can switch identities and, once logged into the directory, switch to the end user's identity. It can perform operations on the end user's behalf, using the authorization appropriate to that particular end user.

●　public key

In public-key cryptography, this key is made public to all. It is primarily used for encryption but can be used for verifying signatures. See public and private key pair

●　public key encryption

The process where the sender of a message encrypts the message with the public key of the recipient. Upon delivery, the message is decrypted by the recipient using its private key.

●　public key infrastructure (PKI)

Information security technology utilizing the principles of public key cryptography. Public key cryptography involves encrypting and decrypting information using a shared public and private key pair. Provides for secure, private communications within a public network.

●　public and private key pair

A set of two numbers used for encryption and decryption, where one is called the private key and the other is called the public key. Public keys are typically made widely available, while private keys are held by their respective owners. Though mathematically related, it is generally viewed as computationally infeasible to derive the private key from the public key. Public and private keys are used only with asymmetric encryption algorithms, also called public-key encryption algorithms, or public-key cryptosystems. Data encrypted with either a public key or a private key from a key pair can be decrypted with its associated key from the key-pair. However, data encrypted with a public key cannot be decrypted with the same public key, and data enwrapped with a private key cannot be decrypted with the same private key.

●　RADIUS

Remote Authentication Dial-In User Service (RADIUS) is a client/server protocol and software that enables remote access servers to communication with a central server to authenticate dial-in users and authorize their access to the requested system or service.

●　realm

1. Short for identity management realm. 2. A Kerberos object. A set of clients and servers operating under a single key distribution center/ticket-granting service (KDC/TGS). Services (see kservice) in different realms that share the same name are unique.

●　realm Oracle Context

An Oracle Context that is part of an identity management realm in Oracle Internet Directory.

●　registry

A Windows repository that stores configuration information for a computer.

●　remote computer

A computer on a network other than the local computer.

●　root key certificate

See trusted certificate

●　schema

1. Database schema: A named collection of objects, such as tables, views, clusters, procedures, packages, attributes, object classes, and their corresponding matching rules, which are associated with a particular user. 2. LDAP directory schema: The collection of attributes, object classes, and their corresponding matching rules.

●　schema mapping

See user-schema mapping

●　Secure Hash Algorithm (SHA)

An algorithm that assures data integrity by generating a 160-bit cryptographic message digest value from given data. If as little as a single bit in the data is modified, the Secure Hash Algorithm checksum for the data changes. Forgery of a given data set in a way that will cause the Secure Hash Algorithm to generate the same result as that for the original data is considered computationally infeasible.

An algorithm that takes a message of less than 264 bits in length and produces a 160-bit message digest. The algorithm with its larger message digest makes it more secure against brute-force collision and inversion attacks.

●　Secure Sockets Layer (SSL)

●　server

A provider of a service.

●　service

1. A network resource used by clients; for example, an Oracle database server.

2. An executable process installed in the Windows registry and administered by Windows. Once a service is created and started, it can run even when no user is logged on to the computer.

●　service name

For Kerberos-based authentication, the kservice portion of a service principal.

●　service principal

See principal

●　service table

In Kerberos authentication, a service table is a list of service principals that exist on a kinstance. This information must be extracted from Kerberos and copied to the Oracle server computer before Kerberos can be used by Oracle.

●　service ticket

Trusted information used to authenticate the client. A ticket-granting ticket, which is also known as the initial ticket, is obtained by directly or indirectly running okinit and providing a password, and is used by the client to ask for service tickets. A service ticket is used by a client to authenticate to a service.

●　session key

A key shared by at least two parties (usually a client and a server) that is used for data encryption for the duration of a single communication session. Session keys are typically used to encrypt network traffic; a client and a server can negotiate a session key at the beginning of a session, and that key is used to encrypt all network traffic between the parties for that session. If the client and server communicate again in a new session, they negotiate a new session key.

●　session layer

A network layer that provides the services needed by the presentation layer entities that enable them to organize and synchronize their dialogue and manage their data exchange. This layer establishes, manages, and terminates network sessions between the client and server. An example of a session layer is Network Session.

●　SHA

See Secure Hash Algorithm (SHA)

●　shared schema

A database or application schema that can be used by multiple enterprise users. Oracle Advanced Security supports the mapping of multiple enterprise users to the same shared schema on a database, which lets an administrator avoid creating an account for each user in every database. Instead, the administrator can create a user in one location, the enterprise directory, and map the user to a shared schema that other enterprise users can also map to. Sometimes called user/schema separation.

●　single key-pair wallet

A PKCS #12-format wallet that contains a single user certificate and its associated private key. The public key is imbedded in the certificate.

●　single password authentication

The ability of a user to authenticate with multiple databases by using a single password. In the Oracle Advanced Security implementation, the password is stored in an LDAP-compliant directory and protected with encryption and Access Control Lists.

●　single sign-on (SSO)

The ability of a user to authenticate once, combined with strong authentication occurring transparently in subsequent connections to other databases or applications. Single sign-on lets a user access multiple accounts and applications with a single password, entered during a single connection. Single password, single authentication. Oracle Advanced Security supports Kerberos, DCE, and SSL-based single sign-on.

●　smart card

A plastic card (like a credit card) with an embedded integrated circuit for storing information, including such information as user names and passwords, and also for performing computations associated with authentication exchanges. A smart card is read by a hardware device at any client or server.

A smartcard can generate random numbers which can be used as one-time use passwords. In this case, smartcards are synchronized with a service on the server so that the server expects the same password generated by the smart card.

●　sniffer

Device used to surreptitiously listen to or capture private data traffic from a network.

●　sqlnet.ora file

A configuration file for the client or server that specifies:

Client domain to append to unqualified service names or net service names
Order of naming methods the client should use when resolving a name
Logging and tracing features to use
Route of connections
Preferred Oracle Names servers
External naming parameters
Oracle Advanced Security parameters

The sqlnet.ora file typically resides in $ORACLE_HOME/network/admin on UNIX platforms and ORACLE_BASE\ORACLE_HOME\network\admin on Windows platforms.

●　SSO

See single sign-on (SSO)

●　System Global Area (SGA)

A group of shared memory structures that contain data and control information for an Oracle instance.

●　system identifier (SID)

A unique name for an Oracle instance. To switch between Oracle databases, users must specify the desired SID. The SID is included in the CONNECT DATA parts of the connect descriptor in a tnsnames.ora file, and in the definition of the network listener in a listener.ora file.

●　ticket

A piece of information that helps identify who the owner is. See service ticket.

●　tnsnames.ora

A file that contains connect descriptors; each connect descriptor is mapped to a net service name. The file may be maintained centrally or locally, for use by all or individual clients. This file typically resides in the following locations depending on your platform:

(UNIX) ORACLE_HOME/network/admin
(Windows) ORACLE_BASE\ORACLE_HOME\network\admin

●　token card

A device for providing improved ease-of-use for users through several different mechanisms. Some token cards offer one-time passwords that are synchronized with an authentication service. The server can verify the password provided by the token card at any given time by contacting the authentication service. Other token cards operate on a challenge-response basis. In this case, the server offers a challenge (a number) which the user types into the token card. The token card then provides another number (cryptographically-derived from the challenge), which the user then offers to the server.

●　transport layer

A networking layer that maintains end-to-end reliability through data flow control and error recovery methods. Oracle Net Services uses Oracle protocol supports for the transport layer.

●　trusted certificate

A trusted certificate, sometimes called a root key certificate, is a third party identity that is qualified with a level of trust. The trusted certificate is used when an identity is being validated as the entity it claims to be. Typically, the certificate authorities you trust are called trusted certificates. If there are several levels of trusted certificates, a trusted certificate at a lower level in the certificate chain does not need to have all its higher level certificates reverified.

●　trusted certificate authority

See certificate authority

●　trust point

See trusted certificate

●　username

A name that can connect to and access objects in a database.

●　user-schema mapping

An LDAP directory entry that contains a pair of values: the base in the directory at which users exist, and the name of the database schema to which they are mapped. The users referenced in the mapping are connected to the specified schema when they connect to the database. User-schema mapping entries can apply only to one database or they can apply to all databases in a domain. See shared schema

●　user/schema separation

See shared schema

●　user search base

The node in the LDAP directory under which the user resides.

●　views

Selective presentations of one or more tables (or other views), showing both their structure and their data.

●　wallet

A wallet is a data structure used to store and manage security credentials for an individual entity. A Wallet Resource Locator (WRL) provides all the necessary information to locate the wallet.

●　wallet obfuscation

Wallet obfuscation is used to store and access an Oracle wallet without querying the user for a password prior to access (supports single sign-on (SSO)).

●　Wallet Resource Locator

A wallet resource locator (WRL) provides all necessary information to locate a wallet. It is a path to an operating system directory that contains a wallet.

●　Windows native authentication

An authentication method that enables a client single login access to a Windows server and a database running on that server.

●　WRL

See Wallet Resource Locator

●　X.509

An industry-standard specification for digital certificates.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　assembly

Assembly is the Microsoft term for the module that is created when a DLL or .EXE is complied by a .NET compiler.

●　Common Language Runtime

Microsoft Common Language Runtime (CLR) is the component of the .NET framework that allows many languages to create and develop applications using the same library.

●　Dynamic Link Library (DLL)

An executable file that a Windows application can load when needed.

●　external procedure

A function written in a third-generation language (3GL), such as C, and callable from within PL/SQL or SQL as if it were a PL/SQL function or procedure.

●　implicit database session

The database session of the caller.

●　Microsoft .NET Framework Class Library

The Microsoft .NET Framework Class Library provides the classes for the .NET framework model.

●　namespace

.NET:

A namespace is naming device for grouping related types. More than one namespace can be contained in an assembly.
XML Documents:

A namespace describes a set of related element names or attributes within an XML document.

●　Oracle Net Services

The Oracle client/server communication software that offers transparent operation to Oracle tools or databases over any type of network protocol and operating system.

●　PL/SQL

Oracle's procedural language extension to SQL.

●　result set

The output of a SQL query, consisting of one or more rows of data.

●　stored function

A stored function is a PL/SQL block that Oracle stores in the database and can be executed from an application.

●　stored procedure

A stored procedure is a PL/SQL block that Oracle stores in the database and can be executed from an application.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　Oracle Active Data Guard option

A physical standby database can be open for read-only access while Redo Apply is active if a license for the Oracle Active Data Guard option has been purchased. This capability, known as real-time query, also provides the ability to have block-change tracking on the standby database, thus allowing incremental backups to be performed on the standby.

●　clusterwide failure

The whole cluster hosting the Oracle RAC database is unavailable or fails. This includes failures of nodes in the cluster, and any other components that result in the cluster being unavailable and the Oracle database and instances on the site being unavailable.

●　computer failure

An outage that occurs when the system running the database becomes unavailable because it has crashed or is no longer accessible.

●　data corruption

A corrupt block is a block that has been changed so that it differs from what Oracle Database expects to find. Block corruptions fall under two categories: physical and logical block corruptions.

●　hang or slow down

Hang or slow down occurs when the database or the application cannot process transactions because of a resource or lock contention. Perceived hang can be caused by lack of system resources.

●　human error

An outage that occurs when unintentional or malicious actions are committed that cause data in the database to become logically corrupt or unusable. The service level impact of a human error outage can vary significantly depending on the amount and critical nature of the affected data.

●　logical unit numbers (LUNs)

Three-bit identifiers used on a SCSI bus to distinguish between up to eight devices (logical units) with the same SCSI ID.

●　lost write

A lost write is another form of data corruption that can occur when an I/O subsystem acknowledges the completion of the block write, while in fact the write did not occur in the persistent storage. No error is reported by the I/O subsystem back to Oracle.

●　MAA environment

The Maximum Availability architecture provides the most comprehensive set of solutions for both unplanned and because it inherits the capabilities and advantages of both Oracle Database 11g with Oracle RAC and Oracle Database 11g with Data Guard.

MAA involves high availability best practices for all Oracle products across the entire technology stack—Oracle Database, Oracle WebLogic Server, Oracle Applications, Oracle Collaboration Suite, and Enterprise Manager.

●　network server processes

The Data Guard network server processes, also referred to as LNSn processes, on the primary database perform a network send to the RFS process on the standby database. There is one network server process for each destination.

●　real-time query

If a license for the Oracle Active Data Guard option has been purchased, you can open a physical standby database while Redo Apply continues to apply redo data received from the primary database.

●　recovery point objective (RPO)

The maximum amount of data an IT-based business process may lose before causing harm to the organization. RPO indicates the data-loss tolerance of a business process or an organization in general. This data loss is often measured in terms of time, for example, five hours or two days worth of data loss.

●　recovery time objective (RTO)

The maximum amount of time that an IT-based business process can be down before the organization suffers significant material losses. RTO indicates the downtime tolerance of a business process or an organization in general.

●　site failure

An outage that occurs when an event causes all or a significant portion of an application to stop processing or slow to an unusable service level. A site failure may affect all processing at a data center, or a subset of applications supported by a data center.

●　snapshot standby database

An updatable standby database that you create from a physical standby database. A snapshot standby database receives and archives redo data received from the primary database, but the snapshot standby database does not apply redo data from the primary database while the standby database is open for read/write I/O. Thus, the snapshot standby typically diverges from the primary database over time. Moreover, local updates to the snapshot standby database cause additional divergence. However, a snapshot standby protects the primary database because the snapshot standby can be converted back into a physical standby database.

●　storage failure

An outage that occurs when the storage holding some or all of the database contents becomes unavailable because it has shut down or is no longer accessible.

●　transient logical standby database

A transient logical standby database is a physical standby database that has been temporarily converted into a logical standby database to perform a rolling database upgrade.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　audio data

Media data produced by an audio recorder, an audio source, or by program algorithms. Audio recording devices take analog or continuous signals and convert them into digital values with specific audio characteristics.

●　codecs

Digital compression and decompression schemes.

●　content metadata

Data that describes the content of image media, such as the name of the photographer, and the date and time when a photograph was taken.

●　DICOM content

Standalone DICOM Information Objects that are encoded according to the data structure and encoding definitions of PS 3.10-2007 of the DICOM standard (commonly referred to as DICOM Part 10 files). For more information about DICOM Information Objects, see the DICOM standard, which is available worldwide from the NEMA Web site at

http://medical.nema.org/

●　DICOM data

See DICOM content.

●　embedded metadata

Metadata that is stored with image data in the image file format.

●　heterogeneous media data

Assorted media data, such as audio data, image data, video data, and other types of media data. The data can have a variety of formats, depending upon the application that generated it.

●　image data

Media data produced by a document or photograph scanner, a video source, other specialized image capture devices, or by program algorithms. Image capture devices take analog or continuous signals and convert them into digital values on a two-dimensional grid of data points known as pixels. Devices involved in the capture and display of images are under application control.

●　image interchange format

A well-defined organization and use of image attributes, data, and often compression schemes that enables different applications to create, exchange, and use images. Interchange formats are often stored as disk files.

●　image metadata format

Standard protocols and techniques used to store image metadata within an image file. Formats include: EXIF, IPTC-IIM, and XMP.

●　Java servlets

Java classes that dynamically process HTTP requests and construct HTTP responses.

●　JavaServer Pages (JSP)

See JSP.

●　JSP

JavaServer Pages, Java text-based documents that execute as Java servlets, but which permit a more natural approach to creating static content than using servlets.

●　lossless compression schemes

Compression schemes that squeeze an image so that when it is decompressed, the resulting image is bit-for-bit identical with the original.

●　lossy compression schemes

Compression schemes that do not result in an identical image when decompressed, but rather, one in which the changes may be imperceptible to the human eye. Lossy schemes generally provide higher compression than lossless compression schemes.

●　media data

Data from audio, image, DICOM format medical images and other objects, video, or other heterogeneous media.

●　metadata

Information about media data, such as object length, compression type, or format.

●　methods

Procedures that can be performed on objects, such as getContent( ) or setProperties( ).

●　Oracle interMedia

In Oracle Database 11g Release 1 (11.1), the name Oracle interMedia was changed to Oracle Multimedia.

●　ORDAudio

Object relational type for audio data characteristics.

●　ORDDicom

Object relational type for characteristics of DICOM content produced by medical devices. See Oracle Multimedia DICOM Developer's Guide for more information about this object type.

●　ORDDoc

Object relational type for heterogeneous data characteristics.

●　ORDImage

Object relational type for image data characteristics.

●　ORDSource

Object relational type that stores data source information for audio, heterogeneous, image, and video data characteristics.

●　ORDVideo

Object relational type for video data characteristics.

●　portlets

Summarized versions of applications and Web content situated in defined regions of a Web page that are accessible through enterprise portals.

●　protocols

Image interchange formats exchanged in a sequential fashion over a network.

●　technical metadata

Data that describes image media in a technical sense, such as the height and width of an image, in pixels, or the type of compression used to store the image.

●　video data

Media data produced by a video recorder, a video camera, digitized animation video, other specialized video recording devices, or by program algorithms. Some video recording devices take analog or continuous signals and convert them into digital values with specific video characteristics.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　administrator-managed database

An administrator-managed database is a database created on nodes that are not part of a server pool and are managed by the database or clusterware administrator.

●　all node patching

A method of applying patches to the nodes in a cluster. When using the all node patching method, all the nodes in the Real Application Clusters are initially brought down and the patch is applied on all the nodes. After the patch is applied to all nodes, then the nodes are brought back up.

●　Automatic Workload Repository (AWR)

A built-in repository that exists in every Oracle Database. At regular intervals, the Oracle Database makes a snapshot of all of its vital statistics and workload information and stores them in the AWR.

●　cache coherency

The synchronization of data in multiple caches so that reading a memory location through any cache returns the most recent data written to that location through any other cache. Sometimes called cache consistency.

●　Cache Fusion

A diskless cache coherency mechanism in Oracle Real Application Clusters that provides copies of blocks directly from a holding instance's memory cache to a requesting instance's memory cache.

●　cluster

Multiple interconnected computers or servers that appear as if they are one server to end users and applications.

●　cluster database

The generic term for an Oracle Real Application Clusters database.

●　cluster file system

A distributed file system that is a cluster of servers that collaborate to provide high performance service to their clients. Cluster file system software deals with distributing requests to storage cluster components.

●　Cluster Synchronization Services (CSS)

An Oracle Clusterware component that discovers and tracks the membership state of each node by providing a common view of membership across the cluster. CSS also monitors process health, specifically the health of the database instance. The Global Enqueue Service Monitor (LMON), a background process that monitors the health of the cluster database environment and registers and de-registers from CSS. See also, OCSSD.

●　Cluster Verification Utility (CVU)

A tool that verifies a wide range of Oracle RAC-specific components such as shared storage devices, networking configurations, system requirements, Oracle Clusterware, groups, and users.

●　CRSD

A Linux or UNIX process that performs high availability recovery and management operations such as maintaining the OCR. Also manages application resources and runs as root user (or by a user in the admin group on Mac operating system X-based systems) and restarts automatically upon failure.

●　Distributed Transaction Processing (DTP)

The paradigm of distributed transactions, including both XA-type externally coordinated transactions, and distributed-SQL-type (database links in Oracle) internally coordinated transactions.

●　Dynamic Host Configuration Protocol (DHCP)

A network application protocol used by devices (DHCP clients) to obtain configuration information for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual intervention.

●　Enterprise Manager Configuration Assistant (EMCA)

A graphical user interface-based configuration assistant that you can use to configure Enterprise Manager features.

●　Event Manager (EVM)

The background process that publishes Oracle Clusterware events. EVM scans the designated callout directory and runs all scripts in that directory when an event occurs.

●　Event Manager Daemon (EVMD)

A Linux or UNIX event manager daemon that starts the racgevt process to manage callouts.

●　Fast Application Notification (FAN)

Applications can use FAN to enable rapid failure detection, balancing of connection pools after failures, and re-balancing of connection pools when failed components are repaired. The FAN notification process uses system events that Oracle publishes when cluster servers become unreachable or if network interfaces fail.

●　Fast Connection Failover

Fast Connection Failover provides high availability to FAN integrated clients, such as clients that use JDBC, OCI, or ODP.NET. If you configure the client to use fast connection failover, then the client automatically subscribes to FAN events and can react to database UP and DOWN events. In response, Oracle gives the client a connection to an active instance that provides the requested database service.

●　forced disk write

In Oracle Real Application Clusters, a particular data block can only be modified by one instance at a time. If one instance modifies a data block that another instance needs, then whether a forced disk write is required depends on the type of request submitted for the block.

●　Free pool

A default server pool used in policy-based cluster and capacity management of Oracle Clusterware resources. The free pool contains servers that are not assigned to any server pool.

●　General Parallel File System (GPFS)

General Parallel File System (GPFS) is a shared-disk IBM file system product that provides data access from all of the nodes in a homogenous or heterogeneous cluster.

●　Global Cache Service (GCS)

Process that implement Cache Fusion. It maintains the block mode for blocks in the global role. It is responsible for block transfers between instances. The Global Cache Service employs various background processes such as the Global Cache Service Processes (LMSn) and Global Enqueue Service Daemon (LMD).

●　Global Cache Service Processes (LMSn)

Processes that manage remote messages. Oracle RAC provides for up to 10 Global Cache Service Processes.

●　Global Cache Service (GCS) resources

Global resources that coordinate access to data blocks in the buffer caches of multiple Oracle RAC instances to provide cache coherency.

●　global database name

The full name of the database that uniquely identifies it from any other database. The global database name is of the form database_name.database_domain—for example: TEST.US.EXAMPLE.COM

●　global dynamic performance views (GV$)

Dynamic performance views storing information about all open instances in an Oracle Real Application Clusters cluster. (Not only the local instance.) In contrast, standard dynamic performance views (V$) only store information about the local instance.

●　Global Enqueue Service (GES)

A service that coordinates enqueues that are shared globally.

●　Global Enqueue Service Daemon (LMD)

The resource agent process that manages requests for resources to control access to blocks. The LMD process also handles deadlock detection and remote resource requests. Remote resource requests are requests originating from another instance.

●　Global Enqueue Service Monitor (LMON)

The background LMON process monitors the entire cluster to manage global resources. LMON manages instance deaths and the associated recovery for any failed instance. In particular, LMON handles the part of recovery associated with global resources. LMON-provided services are also known as Cluster Group Services.

●　Global Services Daemon (GSD)

A component that receives requests from SRVCTL to execute administrative job tasks, such as startup or shutdown. The command is executed locally on each node, and the results are returned to SRVCTL. GSD is installed on the nodes by default.

●　Grid home

The Oracle Home directory for the Oracle Grid Infrastructure for a cluster for a cluster software installation, which includes Oracle Clusterware and Oracle ASM.

●　grid infrastructure

The software that provides the infrastructure for an enterprise grid architecture. Oracle Database 11g release 2 (11.2) combines these infrastructure products into one software bundle called Oracle Grid Infrastructure for a cluster. In an Oracle cluster, Oracle Grid Infrastructure for a cluster includes Oracle Clusterware and Oracle Automatic Storage Management (Oracle ASM). For a standalone Oracle Database server, Oracle Grid Infrastructure for a cluster includes Oracle Restart and Oracle ASM.

●　Grid Naming Service (GNS)

A generic service which resolves the names of hosts in a delegated normal DNS zone by mapping them to IP addresses within the zone. GNS enables the use of Dynamic Host Configuration Protocol (DHCP) address for Oracle RAC database nodes, simplifying deployment. GNS also resolves host names passed back from a SCAN listener.

●　high availability

Systems with redundant components that provide consistent and uninterrupted service, even following hardware or software failures. This involves some degree of redundancy.

●　High Availability Cluster Multi-Processing (HACMP)

High Availability Cluster Multi-Processing is an IBM AIX-based high availability cluster software product. HACMP has two major components: high availability (HA) and cluster multi-processing (CMP).

●　instance

For an Oracle RAC database, each node in a cluster usually has one instance of the running Oracle software that references the database. When a database is started, Oracle allocates a memory area called the System Global Area (SGA) and starts one or more Oracle processes. This combination of the SGA and the Oracle processes is called an instance. Each instance has unique Oracle System Identifier (SID), instance name, rollback segments, and thread ID.

●　instance membership recovery

The method used by Oracle RAC guaranteeing that all cluster members are functional or active. IMR polls and arbitrates the membership. Any members that do not show a heartbeat by way of the control file or who do not respond to periodic activity inquiry messages are presumed terminated.

●　instance name

Represents the name of the instance and is used to uniquely identify a specific instance when clusters share common services names. The instance name is identified by the INSTANCE_NAME parameter in the instance initialization file, initsid.ora. The instance name equals the Oracle System Identifier (sid).

●　instance number

A number that associates extents of data blocks with particular instances. The instance number enables you to start an instance and ensure that it uses the extents allocated to it for inserts and updates. This ensures that an instance does not use space allocated for other instances.

●　interconnect

The private network communication link that is used to synchronize the memory cache of the nodes in the cluster.

●　Logical Volume Manager (LVM)

A generic term that describes Linux or UNIX subsystems for online disk storage management.

●　Inter-Process Communication (IPC)

A high-speed operating system-dependent transport component. The IPC transfers messages between instances on different nodes. Also referred to as the interconnect.

●　Master Boot Record (MBR)

A program that executes when a computer starts. Typically, the MBR resides on the first sector of a local hard disk. The program begins the startup process by examining the partition table to determine which partition to use for starting the computer. The MBR program then transfers control to the boot sector of the startup partition, which continues the startup process.

●　minimum downtime patching

In minimum downtime patching, the nodes are divided into two sets. The first set is shut down and the patch is applied to it. The second set is then shut down. The first set is brought up and then the patch is applied to the second set. After the patch is applied to the second set, those nodes are also brought up, finishing the patching operation.

●　multicast Domain Name Server (mDNS)

A part of Zero Configuration Networking (Zeroconf), mDNS provides the ability to address hosts using DNS-like names without the need of an existing, managed DNS server.

●　Network Attached Storage (NAS)

Storage that is attached to a server by way of a network.

●　Network Interface Card (NIC)

A card that you insert into a computer to connect the computer to a network.

●　network switch

A hardware device that connects computers within a network.

●　Network Time Protocol (NTP)

An Internet standard protocol, built on top of TCP/IP, that ensures the accurate synchronization to the millisecond of the computer clock times in a network of computers.

●　node

A node is a computer on which the Oracle Clusterware software is installed or will be installed.

●　Object Link Manager (OLM)

The Oracle interface that maps symbolic links to logical drives and displays them in the OLM graphical user interface.

●　OCSSD

A Linux or UNIX process that manages the Cluster Synchronization Services (CSS) daemon. Manages cluster node membership and runs as oracle user; failure of this process results in cluster restart.

●　optimal flexible architecture (OFA)

A set of file naming and configuration guidelines created to ensure reliable Oracle installations that require little maintenance.

●　Oracle Base directory

The mountpoint for all software installations performed by a particular user. An Oracle base directory can contain multiple Oracle homes for Oracle software products, either of the same or different releases, all installed by the same operating system user. The Oracle Base directory is also the directory where the software parameter files, log files, trace files, and so on, associated with a specific installation owner are located.

●　Oracle Cluster File System (OCFS)

The Oracle proprietary cluster file system software that is available for Linux and Windows platforms.

●　Oracle Cluster Registry (OCR)

The Oracle RAC configuration information repository that manages information about the cluster node list and instance-to-node mapping information. The OCR also manages information about Oracle Clusterware resource profiles for customized applications.

●　Oracle Clusterware

This is clusterware that is provided by Oracle to manage cluster database processing including node membership, group services, global resource management, and high availability functions.

●　Oracle Home directory

The binary location for a particular software installation.

Typically The Oracle Home directory is a subdirectory of the Oracle Base directory for the software installation owner. However, in the case of Oracle Grid Infrastructure for a cluster, the Oracle Home directory (in this case, the Grid home) is located outside of the Oracle Base directory for the Oracle Grid Infrastructure for a cluster installation owner, because the path of the Grid home is changed to root ownership.

●　Oracle Interface Configuration Tool (OIFCFG)

A command-line tool for both single-instance Oracle databases and Oracle RAC databases that enables you to allocate and de-allocate network interfaces to components, direct components to use specific network interfaces, and retrieve component configuration information. The Oracle Universal Installer (OUI) also uses OIFCFG to identify and display available interfaces.

●　Oracle Inventory directory

The Oracle Inventory directory is the central inventory location for all Oracle software installed on a server.

●　Oracle Notification Services (ONS)

A publish and subscribe service for communicating information about all FAN events.

●　Oracle Universal Installer (OUI)

A tool to install Oracle Clusterware, the Oracle relational database software, and the Oracle Real Application Clusters software. You can also use the Oracle Universal Installer to launch the Database Configuration Assistant (DBCA).

●　policy-managed database

A policy-managed database is created using a server pool. Oracle Clusterware allocates and reassigns capacity based on policies you define, enabling faster resource failover and dynamic capacity assignment.

●　raw device

A disk drive that does not yet have a file system set up. Raw devices are used for Oracle Real Application Clusters because they enable the sharing of disks. See also raw partition.

●　raw partition

A portion of a physical disk that is accessed at the lowest possible level. A raw partition is created when an extended partition is created and logical partitions are assigned to it without any formatting. Once formatting is complete, it is called a cooked partition. See also raw device.

●　Recovery Manager (RMAN)

An Oracle tool that enables you to back up, copy, restore, and recover data files, control files, and archived redo logs. It is included with the Oracle server and does not require separate installation. You can invoke RMAN as a command line utility from the operating system (O/S) prompt or use the GUI-based Enterprise Manager Backup Manager.

●　redo thread

The redo generated by a database instance.

●　rolling patching

In Rolling Patching, one node (or group of nodes) is shutdown, the patch applied and the node brought back up again. This is repeated for each node in the cluster until all the nodes in the Real Application Clusters are patched.

●　Run-time Connection Load Balancing

Enables Oracle to make intelligent service connection decisions based on the connection pool that provides the optimal service for the requested application based on current workloads. The JDBC, ODP.NET, and OCI clients are integrated with the load balancing advisory; you can use any of these client environments to provide run-time connection load balancing.

●　scalability

The ability to add additional nodes to Oracle Real Application Clusters applications and achieve markedly improved scale-up and speed-up.

●　SCAN

A single name, or network alias, for the cluster. Oracle Database 11g database clients use SCAN to connect to the database. SCAN can resolve to multiple IP addresses, reflecting multiple listeners in the cluster handling public client connections.

●　Secure Shell (SSH)

A program for logging into a remote computer over a network. You can use SSH to execute commands on a remote computer and to move files from one computer to another. SSH uses strong authentication and secure communications over insecure channels.

●　Server Control (SRVCTL) Utility

Server Management (SRVM) comprises the components required to operate Oracle Enterprise Manager in Oracle Real Application Clusters. The SRVM components, such as the Intelligent Agent, Global Services Daemon, and SRVCTL, enable you to manage cluster databases running in heterogeneous environments through an open client/server architecture using Oracle Enterprise Manager.

●　server pool

A server pool is a logical division of nodes in a cluster into a group to support policy-managed databases.

●　services

Entities that you can define in Oracle RAC databases that enable you to group database workloads and route work to the optimal instances that are assigned to offer the service.

●　shared everything

A database architecture in which all instances share access to all of the data.

●　singleton services

Services that run on only one instance at any one time. By defining the Distributed Transaction Property (DTP) property of a service, you can force the service to be a singleton service.

●　split brain syndrome

Where two or more instances attempt to control a cluster database. In a two-node environment, for example, one instance attempts to manage updates simultaneously while the other instance attempts to manage updates.

●　system identifier (SID)

The Oracle system identifier (SID) identifies a specific instance of the running Oracle software. For an Oracle Real Application Clusters database, each node within the cluster has an instance referencing the database.

●　thread

Each Oracle instance has its own set of online redo log groups. These groups are called a thread of online redo. In non-Oracle Real Application Clusters environments, each database has only one thread that belongs to the instance accessing it. In Oracle Real Application Clusters environments, each instance has a separate thread, that is, each instance has its own online redo log. Each thread has its own current log member.

●　thread number

An identifier for the redo thread to be used by an instance, specified by the INSTANCE_NUMBER initialization parameter. You can use any available redo thread number but an instance cannot use the same redo thread number as another instance.

●　transparent application failover (TAF)

A run-time failover for high-availability environments, such as Oracle Real Application Clusters, TAF refers to the failover and re-establishment of application-to-service connections. It enables client applications to automatically reconnect to the database if the connection fails, and optionally resume a SELECT statement that was in progress. This reconnect happens automatically from within the Oracle Call Interface (OCI) library.

●　voting disk

A file that manages information about node membership.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　Automatic Workload Repository (AWR)

A built-in repository that exists in every Oracle database. At regular intervals, Oracle Database makes a snapshot of all of its vital statistics and workload information and stores them in the AWR.

●　administrator-managed database

A database that you specifically define on which servers it can run, and where services can run within the database.

●　cache coherency

The synchronization of data in multiple caches so that reading a memory location through any cache will return the most recent data written to that location through any other cache. Sometimes called cache consistency.

●　Cache Fusion

A diskless cache coherency mechanism in Oracle RAC that provides copies of blocks directly from a holding instance's memory cache to a requesting instance's memory cache.

●　cardinality

The number of database instances you want running during normal operations.

●　cluster

Multiple interconnected computers or servers that appear as if they are one server to end users and applications.

●　cluster file system

●　cluster database

The generic term for a Oracle RAC database.

●　Cluster Ready Services Daemon (CRSD)

The primary Oracle Clusterware process that performs high availability recovery and management operations, such as maintaining OCR. Also manages application resources and runs as root user (or by a user in the admin group on Mac OS X-based systems) and restarts automatically upon failure.

●　Cluster Synchronization Services (CSS)

●　Cluster Time Synchronization Service

A time synchronization mechanism that ensures that all internal clocks of all nodes in a cluster are synchronized.

●　Cluster Verification Utility (CVU)

A tool that verifies a wide range of Oracle RAC components such as shared storage devices, networking configurations, system requirements, Oracle Clusterware, groups, and users.

●　Distributed Transaction Processing (DTP)

The paradigm of distributed transactions, including both XA-type externally coordinated transactions, and distributed-SQL-type (database links in Oracle) internally coordinated transactions.

●　Event Manager (EVM)

The background process that publishes Oracle Clusterware events. EVM scans the designated callout directory and runs all scripts in that directory when an event occurs.

●　Event Manager Daemon (EVMD)

A Linux or UNIX event manager daemon that starts the racgevt process to manage callouts.

●　extended distance cluster

A cluster where the nodes in the cluster are separated by greater distances from two buildings across the street, to across a campus or across a city. For availability reasons, the data needs to be located at both sites, and therefore one needs to look at alternatives for mirroring the storage.

●　failure group

A failure group is a subset of the disks in a disk group, which could fail at the same time because they share hardware. Failure groups are used to store mirror copies of data.

●　Fast Application Notification (FAN)

Applications can use FAN to enable rapid failure detection, balancing of connection pools after failures, and re-balancing of connection pools when failed components are repaired. The FAN notification process uses system events that Oracle Database publishes when cluster servers become unreachable or if network interfaces fail.

●　Fast Connection Failover

Fast Connection Failover provides high availability to FAN integrated clients, such as clients that use JDBC, OCI, or ODP.NET. If you configure the client to use fast connection failover, then the client automatically subscribes to FAN events and can react to database UP and DOWN events. In response, Oracle Database gives the client a connection to an active instance that provides the requested database service.

●　forced disk write

In Oracle RAC, a particular data block can only be modified by one instance at a time. If one instance modifies a data block that another instance needs, then whether a forced disk write is required depends on the type of request submitted for the block.

●　General Parallel File System (GPFS)

General Parallel File System (GPFS) is a shared-disk IBM file system product that provides data access from all of the nodes in a homogenous or heterogeneous cluster.

●　Global Cache Service (GCS)

●　Global Cache Service Processes (LMSn)

Processes that manage remote messages. Oracle RAC provides for up to 10 Global Cache Service Processes.

●　Global Cache Service (GCS) resources

Global resources that coordinate access to data blocks in the buffer caches of multiple Oracle RAC instances to provide cache coherency.

●　global database name

The full name of the database that uniquely identifies it from any other database. The global database name is of the form database_name.database_domain—for example: OP.US.FOO.COM

●　global dynamic performance views (GV$)

Dynamic performance views storing information about all open instances in an Oracle RAC cluster. (Not only the local instance.) In contrast, standard dynamic performance views (V$) only store information about the local instance.

●　Global Enqueue Service (GES)

A service that coordinates enqueues that are shared globally.

●　Global Enqueue Service Daemon (LMD)

●　Global Enqueue Service Monitor (LMON)

●　Global Services Daemon (GSD)

●　Oracle Grid Infrastructure

The software that provides the infrastructure for an enterprise grid architecture. In a cluster this software includes Oracle Clusterware and Oracle Automatic Storage Management (Oracle ASM). For a standalone server, this software includes Oracle Restart and Oracle ASM. Oracle Database 11g release 2 (11.2) combines these infrastructure products into one software installation called the Oracle Grid Infrastructure home (Grid_home).

●　Grid Plug and Play Daemon (GPNPD

This process provides access to the Grid Plug and Play profile, and coordinates updates to the profile among the nodes of the cluster to ensure that all of the nodes node have the most recent profile.

●　High Availability Cluster Multi-Processing (HACMP)

High Availability Cluster Multi-Processing is an IBM AIX-based high availability cluster software product. HACMP has two major components: high availability (HA) and cluster multi-processing (CMP).

●　high availability

Systems with redundant components that provide consistent and uninterrupted service, even in the event of hardware or software failures. This involves some degree of redundancy.

●　instance

For an Oracle RAC database, each node in a cluster usually has one instance of the running Oracle software that references the database. When a database is started, Oracle Database allocates a memory area called the System Global Area (SGA) and starts one or more Oracle Database processes. This combination of the SGA and the Oracle Database processes is called an instance. Each instance has unique Oracle System Identifier (SID), instance name, rollback segments, and thread ID.

●　instance membership recovery

The method used by Oracle RAC guaranteeing that all cluster members are functional or active. instance membership recovery polls and arbitrates the membership. Any members that do not show a heartbeat by way of the control file or who do not respond to periodic activity inquiry messages are presumed terminated.

●　instance name

●　instance number

A number that associates extents of data blocks with particular instances. The instance number enables you to start up an instance and ensure that it uses the extents allocated to it for inserts and updates. This will ensure that it does not use space allocated for other instances.

●　interconnect

The communication link between nodes.

●　Logical Volume Manager (LVM)

A generic term that describes Linux or UNIX subsystems for online disk storage management.

●　Interprocess Communication (IPC)

A high-speed operating system-dependent transport component. The IPC transfers messages between instances on different nodes. Also referred to as the interconnect.

●　Master Boot Record (MBR)

A program that executes when a computer starts. Typically, the MBR resides on the first sector of a local hard disk. The program begins the startup process by examining the partition table to determine which partition to use for starting the system. The MBR program then transfers control to the boot sector of the startup partition, which continues the startup process.

●　metric

The rate of change in a cumulative statistic.

●　Network Attached Storage (NAS)

Storage that is attached to a server by way of a network.

●　Network Time Protocol (NTP)

An Internet standard protocol, built on top of TCP/IP, that ensures the accurate synchronization to the millisecond of the computer clock times in a network of computers.

●　Network Interface Card (NIC)

A card that you insert into a computer to connect the computer to a network.

●　node

A node is a computer system on which Oracle RAC and Oracle Clusterware software are installed.

●　Object Link Manager (OLM)

The Oracle interface that maps symbolic links to logical drives and displays them in the OLM graphical user interface.

●　OCSSD

A Linux or UNIX process that manages the Cluster Synchronization Services (CSS) daemon. Manages cluster node membership and runs as oracle user; failure of this process results in cluster restart.

●　Oracle Cluster File Systems

Oracle offers two cluster file systems, OCFS for Windows and OCFS2 for Linux. While OCFS for Windows is a proprietary file system, the source for OCFS2 for Linux is available to all under GNUs' General Public License (GPL). The two file systems are not compatible.

●　Oracle Cluster Registry (OCR)

The Oracle RAC configuration information repository that manages information about the cluster node list and instance-to-node mapping information. OCR also manages information about Oracle Clusterware resource profiles for customized applications.

●　Oracle Enterprise Manager Configuration Assistant (EMCA)

A graphical user interface-based configuration assistant that you can use to configure Oracle Enterprise Manager features.

●　Oracle Grid Naming Service Daemon (GNSD)

The Oracle Grid Naming Service is a gateway between the cluster mDNS and external DNS servers. The gnsd process performs name resolution within the cluster.

●　Oracle High Availability Services Daemon (OHASD)

This process anchors the lower part of the Oracle Clusterware stack, which consists of processes that facilitate cluster operations.

●　Oracle Interface Configuration Tool (OIFCFG)

A command-line tool for both noncluster Oracle databases and Oracle RAC databases that enables you to allocate and de-allocate network interfaces to components, direct components to use specific network interfaces, and retrieve component configuration information. The Oracle Universal Installer also uses OIFCFG to identify and display available interfaces.

●　Oracle Managed Files

A service that automates naming, location, creation, and deletion of database files such as control files, redo log files, data files and others, based on a few initialization parameters. You can use Oracle Managed Files on top of a traditional file system supported by the host operating system, for example, VxFS or ODM. It can simplify many aspects of the database administration by eliminating the need to devise your own policies for such details.

●　Oracle Notification Service

A publish and subscribe service for communicating information about all FAN events.

●　Oracle Clusterware

This is clusterware that is provided by Oracle to manage cluster database processing including node membership, group services, global resource management, and high availability functions.

●　Oracle Universal Installer

A tool to install Oracle Clusterware, the Oracle relational database software, and the Oracle RAC software. You can also use the Oracle Universal Installer to launch the Database Configuration Assistant (DBCA).

●　policy-managed database

A database that you define as a cluster resource. Management of the database is defined by how you configure the resource, including on which servers the database can run and how many instances of the database are necessary to support the expected workload.

●　raw device

A disk drive that does not yet have a file system set up. Raw devices are used for Oracle RAC because they enable the sharing of disks. See also raw partition.

●　raw partition

●　Recovery Manager (RMAN)

An Oracle tool that enables you to back up, copy, restore, and recover data files, control files, and archived redo logs. It is included with the Oracle server and does not require separate installation. You can run RMAN as a command line utility from the operating system (O/S) prompt or use the GUI-based Oracle Enterprise Manager Backup Manager.

●　result cache

A result cache is an area of memory, either in the SGA or client application memory, that stores the result of a database query or query block for reuse. The cached rows are shared across statements and sessions unless they become stale.

●　Runtime Connection Load Balancing

Enables Oracle Database to make intelligent service connection decisions based on the connection pool that provides the optimal service for the requested application based on current workloads. The JDBC, ODP.NET, and OCI clients are integrated with the load balancing advisory; you can use any of these client environments to provide runtime connection load balancing.

●　scalability

The ability to add additional nodes to Oracle RAC applications and achieve markedly improved scale-up and speed-up.

●　Secure Shell (SSH)

A program for logging into a remote computer over a network. You can use SSH to execute commands on a remote system and to move files from one system to another. SSH uses strong authentication and secure communications over insecure channels.

●　Server Control Utility (SRVCTL)

Server Management (SRVM) comprises the components required to operate Oracle Enterprise Manager in Oracle RAC. The SRVM components, such as the Intelligent Agent, Global Services Daemon, and SRVCTL, enable you to manage cluster databases running in heterogeneous environments through an open client/server architecture using Oracle Enterprise Manager.

●　server

A computer system that has no Oracle software installed upon it.

●　server group

A logical partition of nodes in a cluster into a group that hosts applications, databases, or both. Server groups can be members of other server groups.

●　service level

A measure of the performance of a system.

●　services

Entities that you can define in Oracle RAC databases that enable you to group database workloads and route work to the optimal instances that are assigned to offer the service.

●　shared everything

A database architecture in which all instances share access to all of the data.

●　single client access name (SCAN)

Oracle Database 11g database clients use SCAN to connect to the database. SCAN can resolve to multiple IP addresses, reflecting multiple listeners in the cluster handling public client connections.

●　singleton services

Services that run on only one instance at any one time. By defining the Distributed Transaction Property (DTP) property of a service, you can force the service to be a singleton service.

●　split brain syndrome

●　system identifier (SID)

The Oracle system identifier (SID) identifies a specific instance of the running Oracle software. For an Oracle RAC database, each node within the cluster has an instance referencing the database.

●　transparent application failover (TAF)

A runtime failover for high-availability environments, such as Oracle RAC and Oracle RAC Guard, TAF refers to the failover and re-establishment of application-to-service connections. It enables client applications to automatically reconnect to the database if the connection fails, and optionally resume a SELECT statement that was in progress. This reconnect happens automatically from within the Oracle Call Interface library.

●　voting disk

A file that manages information about node membership.

●　wallet

A wallet is a data structure used to store and manage security credentials for an individual entity.

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

The following are selected terms relevant to the Oracle Database implementation of semantic technologies support. This is not a comprehensive RDF and OWL glossary.

●　apply pattern

Part of a data access constraint defines additional graph patterns to be applied on the resources that match the match pattern before they can be used to construct the query results. See also: match pattern

●　basic graph pattern (BGP)

A set of triple patterns. From the W3C SPARQL Query Language for RDF Recommendation: "SPARQL graph pattern matching is defined in terms of combining the results from matching basic graph patterns. A sequence of triple patterns interrupted by a filter comprises a single basic graph pattern. Any graph pattern terminates a basic graph pattern."

●　clique

A graph in which every node of it is connected to, bidirectionally, every other node in the same graph.

●　Cytoscape

An open source bioinformatics software platform for visualizing molecular interaction networks and integrating these interactions with gene expression profiles and other state data. (See http://www.cytoscape.org/.) An RDF viewer (available for download) is provided as a Cytoscape plug-in.

●　entailment

An object containing precomputed triples that can be inferred from applying a specified set of rulebases to a specified set of models. See also: rulebase

●　extractor policy

A named dictionary entity that determines the characteristics of a semantic index that is created using the policy. Each extractor policy refers, directly or indirectly, to an instance of an extractor type.

●　graph pattern

A combination of triples constructed by combining triple patterns in various ways, including conjunction of triple patterns into groups, optionally using filter conditions, and then combining such groups via connectors similar to disjunctions, outer-joins, and so on. SPARQL querying is based around graph pattern matching.

●　inferencing

The ability to make logical deductions based on rules. Inferencing enables you to construct queries that perform semantic matching based on meaningful relationships among pieces of data, as opposed to just syntactic matching based on string or other values. Inferencing involves the use of rules, either supplied by Oracle or user-defined, placed in rulebases.

●　information extractor

An application that processes unstructured documents and extract meaningful information from them, often using natural-language processing engines with the aid of ontologies.

●　Jena Adapter for Oracle Database

An Oracle-supplied adapter (available for download) for Jena, which is a Java framework for building Semantic Web applications.

●　match pattern

Part of a constraint that determines the type of access restriction it enforces and binds one or more variables to the corresponding data instances accessed in the user query. See also: apply pattern

●　model

A user-created semantic structure that has a model name, and refers to triples stored in a specified table column. Examples in this manual are the Articles and Family models.

●　ontology

A shared conceptualization of knowledge in a particular domain. It consists of a collection of classes, properties, and optionally instances. Classes are typically related by class hierarchy (subclass/ superclass relationship). Similarly, the properties can be related by property hierarchy (subproperty/ superproperty relationship). Properties can be symmetric or transitive, or both. Properties can also have domain, ranges, and cardinality constraints specified for them.

●　OWLPrime

An Oracle-defined subset of OWL capabilities; refers to the elements of the OWL standard supported by the Oracle Database semantic technologies native inferencing engine.

●　reasoning

See inferencing

●　rule

An object that can be applied to draw inferences from semantic data.

●　rulebase

An object that can contain rules. See also: rule

●　rules index

See: entailment

●　semantic index

An index of type MDSYS.SEMCONTEXT, created on textual documents stored in a column of a table, and used with information extractors to locate and extract meaningful information from unstructured documents. See also: information extractor

●　Sesame Adapter for Oracle Database

An Oracle-supplied adapter (available for download) that integrates the popular Sesame Java APIs with Oracle Semantic Technologies support.

●　Simple Knowledge Organization System (SKOS)

A data model that is especially useful for representing thesauri, classification schemes, taxonomies, and other types of controlled vocabulary. SKOS is based on standard semantic web technologies including RDF and OWL, which makes it easy to define the formal semantics for those knowledge organization systems and to share the semantics across applications.

●　triple pattern

Similar to an RDF triple, but allows use of a variable in place of any of the three components (subject, predicate, or object). Triple patterns are basic elements in graph patterns used in SPARQL queries. A triple pattern used in a query against an RDF graph is said to match if, substitution of RDF terms for the variables present in the triple pattern, creates a triple that is present in the RDF graph. See also: graph pattern

Scripting on this page enhances content navigation, but does not change the content in any way.

Glossary

●　action context

Optional information associated with a rule that is interpreted by the client of the rules engine when the rule is evaluated for a message.

●　ANYDATA queue

A queue of type ANYDATA. These queues can stage messages of different types wrapped in an ANYDATA wrapper.

See Also: logical change record (LCR)

●　apply servers

A component of an apply process that includes one or more processes that apply LCRs to database objects as DML or DDL statements or pass the LCRs to their appropriate apply handlers. For user messages, the apply servers pass the messages to the message handler. Apply servers can also enqueue logical change record (LCR) and non-LCR messages specified by the DBMS_APPLY_ADM.SET_ENQUEUE_DESTINATION procedure. If an apply server encounters an error, then it tries to resolve the error with a user-specified error handler. If an apply server cannot resolve an error, then it places the entire transaction, including all of its LCRs, in the error queue.

See Also: logical change record (LCR)

●　apply user

The user in whose security domain an apply process dequeues messages that satisfy its rule sets, applies messages directly to database objects, runs custom rule-based transformations configured for apply process rules, and runs apply handlers configured for the apply process.

●　approximate commit system change number (approximate CSCN)

An SCN value based on the current SCN of the database when a transaction that has enqueued messages into a commit-time queue is committed.

●　archived-log downstream capture process

A downstream capture process that captures changes in archived redo log files copied from the source database to the downstream database.

●　barrier transaction

A DDL transaction or a transaction that includes a row logical change record (row LCR) for which an apply process cannot identify the table rows or the database object by using the destination database data dictionary and virtual dependency definitions.

●　buffered LCR

A logical change record (LCR) that is constructed explicitly by an application and enqueued into the buffered queue portion of an ANYDATA queue.

●　buffered queue

The portion of a queue that uses the Oracle Streams pool to store messages in memory and a queue table to store messages that have spilled from memory.

●　buffered user message

A non-LCR message of a user-defined type that is created explicitly by an application and enqueued into a buffered queue. A buffered user message can be enqueued into the buffered queue portion of an ANYDATA queue or a typed queue.

●　builder server

A component of a capture process that is a process that merges redo records from the preparer server. These redo records either evaluated to TRUE during partial evaluation or partial evaluation was inconclusive for them. The builder server preserves the system change number (SCN) order of these redo records and passes the merged redo records to the capture process.

●　capture database

The database running the capture process that captures changes made to the source database. The capture database and the source database are the same database when the capture process is a local capture process. The capture database and the source database are different when the capture process is a downstream capture process.

●　capture process

An optional Oracle background process that scans the database redo log to capture DML and DDL changes made to database objects. A capture process is an Oracle Streams client.

●　capture user

Either the user in whose security domain a capture process captures changes that satisfy its rule sets and runs custom rule-based transformations configured for capture process rules, or the user in whose security domain a synchronous capture captures changes that satisfy its rule set and runs custom rule-based transformations configured for synchronous capture rules.

●　captured LCR

A logical change record (LCR) that was captured implicitly by a capture process and enqueued into the buffered queue portion of an ANYDATA queue.

See Also: logical change record (LCR)

●　change handler

A special type of statement DML handler that tracks table changes and was created by either the DBMS_STREAMS_ADM.MAINTAIN_CHANGE_TABLE procedure or the DBMS_APPLY_ADM.SET_CHANGE_HANDLER procedure.

●　checkpoint

Information about the current state of a capture process that is stored persistently in the data dictionary of the database running the capture process.

●　checkpoint interval

A regular interval at which a capture process attempts to record a checkpoint.

●　checkpoint retention time

The amount of time that a capture process retains checkpoints before purging them automatically.

●　column list

A list of columns for which an update conflict handler is called when an update conflict occurs for one or more of the columns in the list.

See Also: logical change record (LCR)

●　conflict resolution

Handling a conflict to avoid an apply error. Either prebuilt update conflict handlers or custom conflict handlers can resolve conflicts.

●　consumption

The process of dequeuing an message from a queue.

●　coordinator process

A component of an apply process that is an Oracle background process that gets transactions from the reader server and passes them to apply servers.

●　custom apply

An apply process passes an LCR as a parameter to a user procedure for processing. The user procedure can process the LCR in a customized way.

See Also: logical change record (LCR)

●　custom rule-based transformation

A rule-based transformation that requires a user-defined PL/SQL function to perform the transformation.

●　database supplemental logging

The type of supplemental logging that can apply to the primary key, foreign key, and unique key columns in an entire database.

●　DDL handler

An apply handler that uses a PL/SQL procedure to process DDL LCRs.

●　DDL logical change record (DDL LCR)

A logical change record (LCR) that describes a data definition language (DDL) change.

●　declarative rule-based transformation

A rule-based transformation that covers one of a common set of transformation scenarios for row LCRs. Declarative rule-based transformations are run internally without using PL/SQL.

●　dequeue

To retrieve a message from a queue.

●　destination database

A database where messages are consumed. Messages can be consumed when they are dequeued implicitly from a queue by a propagation or apply process, or messages can be consumed when they are dequeued explicitly by an application, a messaging client, or a user.

See Also: logical change record (LCR)

●　directed network

A network in which propagated messages pass through one or more intermediate databases before arriving at a destination database.

●　DML handler

An apply handler that processes row LCRs.

●　downstream capture process

A capture process that runs on a database other than its source database.

●　downstream database

The database on which a downstream capture process runs.

●　enqueue

To place a message in a queue.

●　error handler

An apply handler that uses a PL/SQL procedure to try to resolve apply errors. An error handler is invoked only when a row logical change record (row LCR) raises an apply process error. Such an error might result from a conflict if no conflict handler is specified or if the update conflict handler cannot resolve the conflict.

●　evaluation context

A database object that defines external data that can be referenced in rule conditions. The external data can exist as variables, table data, or both.

●　exception queue

Messages are transferred to an exception queue if they cannot be retrieved and processed for some reason.

●　explicit capture

The messages are enqueued into a queue by an application or a user.

●　explicit consumption

The messages in a queue are dequeued either by a messaging client when it is invoked by a user or application or by an application or user directly.

●　expression

A combination of one or more values and operators that evaluate to a value.

●　file

In the context of a file group, a reference to a file stored on hard disk. A file is composed of a file name, a directory object, and a file type. The directory object references the directory in which the file is stored on hard disk.

●　file group

A collection of versions.

●　file group repository

A collection of all of the file groups in a database.

●　first SCN

The lowest system change number (SCN) in the redo log from which a capture process can capture changes.

●　global rule

A rule that is relevant either to an entire database or an entire queue.

●　heterogeneous information sharing

Sharing information between Oracle and non-Oracle databases.

●　high-watermark

The system change number (SCN) beyond which no messages have been applied by an apply process.

See Also: logical change record (LCR)

●　message rule

A rule that is relevant only for a user message of a specific message type.

●　messaging client

An optional Oracle Streams client that dequeues persistent LCRs or persistent user messages when it is invoked by an application or a user.

●　negative rule set

A rule set for an Oracle Streams client that results in the Oracle Streams client discarding a message when a rule in the rule set evaluates to TRUE for the message. The negative rule set for an Oracle Streams client always is evaluated before the positive rule set.

●　nonpersistent queue

Nonpersistent queues store messages in memory. They are generally used to provide an asynchronous mechanism to send notifications to all users that are currently connected. Nonpersistent queues were deprecated in Oracle Database 10g Release 2. Oracle recommends that you use buffered messaging instead.

●　nontransactional queue

A queue in which each message is its own transaction.

See Also: logical change record (LCR)

●　real-time downstream capture process

A downstream capture process that can capture changes made at the source database before the changes are archived in an archived redo log file.

●　required checkpoint SCN

The system change number (SCN) that corresponds to the lowest checkpoint interval for which a capture process requires redo data.

●　replication

The process of sharing database objects and data at multiple databases.

●　resolution column

The column used to identify a prebuilt update conflict handler.

See Also: logical change record (LCR)

●　synchronous capture

An optional Oracle Streams client that uses an internal mechanism to capture DML changes made to tables immediately after the changes are made.

●　system-created rule

A rule with a system-generated name that was created using the DBMS_STREAMS_ADM package.

●　table rule

A rule that is relevant only to a particular table.

●　table supplemental logging

The type of supplemental logging that applies to columns in a particular table.

●　tablespace repository

A collection of the tablespace sets in a file group.

●　tag

Data of RAW data type that appears in each redo entry and LCR. You can use tags to modify the behavior of Oracle Streams clients and to track LCRs. Tags can also be used to prevent change cycling.

See Also: logical change record (LCR)

●　topology

See Oracle Streams topology.

●　transaction control directive

A special type of row LCR captured by a capture process or synchronous capture that contains transaction control statements, such as COMMIT and ROLLBACK.

●　transactional queue

A queue in which messages can be grouped into a set that are applied as one transaction.

See Also: logical change record (LCR)

●　value dependency

A virtual dependency definition that defines a table constraint, such as a unique key, or a relationship between the columns of two or more tables.

●　version

A collection of related files.

●　virtual dependency definition

A description of a dependency that is used by an apply process to detect dependencies between transactions being applied at a destination database.

Scripting on this page enhances content navigation, but does not change the content in any way.

About Me

...............................................................................................................................

● 本文来自于Oracle官方文档

● 小麦苗云盘地址：http://blog.itpub.net/26736162/viewspace-1624453/

● QQ群：230161599 微信群：私聊

● 联系我请加QQ好友(642808185)，注明添加缘由

● 版权所有，欢迎分享本文，转载请保留出处

...............................................................................................................................

手机长按下图识别二维码或微信客户端扫描下边的二维码来关注小麦苗的微信公众号：xiaomaimiaolhr，免费学习最实用的数据库技术。

【OH】Glossary Oracle词汇表（下）

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

Glossary

热门文章

最新文章

相关电子书

推荐镜像