A

access method services

The facility that defines and reproduces VSAM key-sequenced data sets.

access path

The path that locates data that is specified in SQL statements. An access path can be indexed or sequential.

active log

The portion of the DB2 log to which log records are written as they are generated. The active log always contains the most recent log records, whereas the archive log holds those records that are older and no longer fit on the active log.

address space

A range of virtual storage pages that is identified by a number (ASID) and a collection of segment and page tables that map the virtual pages to real pages of the computer's memory.

administrative authority

A set of related privileges that DB2 defines. When you grant one of the administrative authorities to a person's ID, the person has all of the privileges that are associated with that administrative authority.

after trigger

A trigger that is defined with the trigger activation time AFTER.

alias

An alternative name that can be used in SQL statements to refer to a table or view in the same or a remote DB2 subsystem.

American National Standards Institute (ANSI)

An organization consisting of producers, consumers, and general interest groups, that establishes the procedures by which accredited organizations create and maintain voluntary industry standards in the United States.

ANSI

American National Standards Institute.

APF

Authorized program facility.

API

Application programming interface.

application

A program or set of programs that perform a task; for example, a payroll application.

application plan

The control structure that is produced during the bind process. DB2 uses the application plan to process SQL statements that it encounters during statement execution.

application process

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

application programming interface (API)

A functional interface that is supplied by the operating system or by a separately orderable licensed program that allows an application program that is written in a high-level language to use specific data or functions of the operating system or licensed program.

application requester

The component on a remote system that generates DRDA requests for data on behalf of an application. An application requester accesses a DB2 database server by using the DRDA application-directed protocol.

application server

The target of a request from a remote application. In the DB2 environment, the application server function is provided by the distributed data facility and is used to access DB2 data from remote applications.

archive log

The portion of the DB2 log that contains log records that have been copied from the active log.

ASCII

An encoding scheme that represents strings in many environments, typically on PCs and workstations. Contrast with EBCDIC and Unicode.

attachment facility

An interface between DB2 and TSO, IMS, CICS, or batch address spaces. An attachment facility allows application programs to access DB2.

attribute

A characteristic of an entity. For example, in database design, the phone number of an employee is one of that employee's attributes.

authorization ID

A string that can be verified for connection to DB2 and to which a set of privileges is allowed. It can represent an individual, an organizational group, or a function, but DB2 does not determine this representation.

authorized program facility (APF)

A facility that permits the identification of programs that are authorized to use restricted functions.

automatic query rewrite

A process that examines an SQL statement that refers to one or more base tables and, if appropriate, rewrites the query so that it performs better. This process can also determine whether to rewrite a query so that it refers to one or more materialized query tables that are derived from the source tables.

auxiliary index

An index on an auxiliary table in which each index entry refers to a LOB.

auxiliary table

A table that stores columns outside the table in which they are defined. Contrast with base table.