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Glossary

A

abnormal termination
(1) The cessation of processing prior to planned termination. (T) (2) A system failure or operator action that causes a job to end unsuccessfully. (3) In DB2, exits that are not under program control, such as a trap or segv.

access path
The method that is selected by the optimizer for retrieving data from a specific table. For example, an access path can involve the use of an index, a sequential scan, or a combination of the two.

access plan
The set of access paths that are selected by the optimizer to evaluate a particular SQL statement. The access plan specifies the order of operations to resolve the execution plan, the implementation methods (such as JOIN), and the access path for each table referenced in the statement.

accounting string
User-defined accounting information that is sent to DRDA servers by DB2 Connect. This information can be specified at one of these locations:

active log
The subset of files consisting of primary and secondary log files that are currently needed by the database manager for crash recovery and rollback. Contrast with archive log.

adjacent nodes
Two nodes connected together by at least one path that connects no other nodes. (T)

administrative authority
A level of authority that gives a user privileges over a set of objects. For example, DBADM authority gives privileges over all objects in a database, and SYSADM authority gives privileges over all objects in a system.

ADSM
ADSTAR Distributed Storage Manager.

ADSTAR Distributed Storage Manager (ADSM)
A client/server product that provides storage management and data access services in a heterogeneous environment. It supports various communication methods, provides administrative facilities to manage the backup and storage of files, and provides facilities for scheduling backup operations.

Advanced Peer-to-Peer Networking (APPN)
An extension to SNA that features greater distributed network control, dynamic definition of network resources, and automated resource registration and directory lookup.

Advanced Peer-to-Peer Networking (APPN) network
A collection of interconnected network nodes and their client end nodes. See also network node.

Advanced program-to-program communication (APPC)
The general facility that characterizes the LU 6.2 architecture and its various implementations in products.

after-image
The updated content of a source table element that is recorded in a change data table or in a database log or journal. Contrast with before-image.

agent
A separate process or thread that carries out all DB2 requests that are made by a particular client application.

aggregate function
Synonym for column function.

alert
An action, such as a beep or warning, that is generated when a performance variable exceeds or falls below its warning or alarm threshold.

alias
In DB2, an alternative name used to identify a table, view, or database.

alias chain
A series of table aliases that refer to each other in a sequential, non-repeating fashion.

alphanumeric
Pertaining to data that consists of letters, digits, and usually other characters, such as punctuation marks. (T) (A)

ambiguous cursor
A cursor that cannot be determined to be updateable or read-only from its definition or context.

API
Application programming interface.

APPC
Advanced program-to-program communication.

application ID
A string that uniquely identifies an application across networks. An ID is generated at the time that the application connects to the database. This ID is known on both the client and the server and can be used to correlate the two parts of the application.

application process
The unit to which resources and locks are allocated. An application process involves the running of one or more programs.

application programming interface (API)
(1) A functional interface supplied by the operating system or by a separately orderable licensed program. It allows an application program written in a high-level language to use specific data or functions of the operating system or the licensed programs. (2) In DB2, a function within the interface. For example, the get error message API.

application requester
A facility that accepts a database request from an application process and passes it to an application server.

application server
The local or remote database manager to which the application process is connected.

Apply program
A replication program that is used to refresh or update a target table, depending on the applicable source-to-target rules. Contrast with Capture program.

Apply qualifier
A character string that identifies subscription definitions that are unique to each instance of the Apply program.

Apply trail table
A replication source table at the control server that records a history of the refreshes and updates performed against target tables.

APPN
Advanced Peer-to-Peer Networking.

APPN network node
Advanced Peer-to-Peer Networking (APPN) network node. Synonymous with network node.

archive log
The set of log files that are closed and are no longer needed for normal processing. These files are retained for use in roll-forward recovery. Contrast with active log.

argument
A value passed to or returned from a function or procedure at run time.

asynchronous
Without regular time relationship; unexpected and unpredictable with respect to the processing of program instructions. Contrast with synchronous.

asynchronous batched update
A process in which all changes to the source are recorded and applied to existing target data at specified intervals. Contrast with asynchronous continuous update.

asynchronous continuous update
A process in which all changes to the source are recorded and applied to existing target data after being committed in the base table. Contrast with asynchronous batched update.

attach
In DB2, to remotely access objects at the instance level.

audit trail
Data, in the form of a logical path linking a sequence of events, used for tracing the transactions that have affected the contents of a record. (T)

authorization
In computer security, the right granted to a user to communicate with or make use of a computer system. (T)

authorization ID
A character string in a statement that designates a set of privileges. It is used by the database manager for authorization checking and as an implicit qualifier for the names of objects such as tables, views, and indexes.

autocommit
To automatically commit the current unit of work after each SQL statement.

automatic rebind
A feature that automatically rebinds an invalidated package without requiring a bind command to be entered manually or a bind file to be present.

auto-registration
A process in which replica and consistent change data tables are automatically defined as replication sources at the target server.

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