A


access path

The method that the database manager selects 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 the optimizer selects 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.



access profile

Contains information a client workstation needs to catalog a remote database stored on a DB2 UDB server.



access token

An object that describes the security context of a process or thread. The information in the token includes the identity and privileges of the user account associated with the process or thread.



active log

The primary and secondary log files that are currently needed for recovery and roll back.



Activity Monitor

The DB2 tool that assists database administrators (DBAs) to monitor application performance and concurrency, resource consumption, and SQL statement usage of a database or database partition. It provides predefined views of application, statement, and SQL cache activity. DBAs can choose to view live monitor data and can record monitor data for further analysis. The tool also gives recommendations to resolve resource utilization problems.



address space

The actual memory that an active program uses.

See also [buffer pool]


Address Windowing Extensions (AWE)

A Windows API that lets user applications use physical non-paged memory beyond the 32-bit virtual address space and have window views to this physical memory from within the application's virtual address space. The AWE API also contributes to both system and application performance.



administrative authority

SYSADM and DBADM authority levels that have full privileges for instance resources and database resources, respectively.



administrative authorization

The process by which DB2 obtains information about the authenticated user, such as the database operations the user may perform and which data objects the user may access.



administration notification log

A list of user-friendly, national language messages that should help database administrators resolve minor issues. Also known as the DB2 notify log.



administrator

A person responsible for administrative tasks such as access authorization and content management. Administrators can also grant levels of authority to users.



Advanced Peer-to-Peer Networking (APPN)

An extension to SNA that features distributed network control, dynamic definition of network resources, and automated resource registration and directory lookup.



Advanced Program-to-Program Communication (APPC)

A protocol that allows interconnected systems to communicate and share the processing of programs. APPC supports Systems Network Architecture and uses the Logical Unit (LU) 6.2 protocol for establishing sessions between systems.



after trigger

A trigger activated after the triggering SQL operation has completed. The triggering operation can be an INSERT, UPDATE, DELETE, fullselect, or SIGNAL SQLSTATE statement.



agent

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



alert

A signal representing the state of an object (such as a database, table space, or instance).



alias

An alternative name used to identify a table, view, database, or nickname. An alias can be used in SQL statements to refer to a table or view.



ambiguous cursor

A cursor is ambiguous if all of the following conditions are true:

  • The SELECT statement is dynamically prepared.

  • The SELECT statement does not include either the FOR READ ONLY clause or the FOR UPDATE clause.

  • The LANGLEVEL bind option is SAA1.

  • The cursor otherwise satisfies the conditions of a deleteable cursor.

An ambiguous cursor is considered read-only if the BLOCKING bind option is ALL; otherwise, it is considered deleteable.



American National Standard Code for Information Interchange (ASCII)

An encoding scheme that represents character strings in many environments, typically on personal computers and workstations.

See also [EBCDIC]
See also [Unicode]


authorized program analysis report (APAR)

A term used in IBM for a description of a problem. It is formally tracked until a solution is provided.



API

See [application programming interface]
APPC

See [Advanced Program-to-Program Communication]
APPL

A VTAM network definition statement used to define a DB2 for z/OS and OS/390 to VTAM application program that uses SNA LU 6.2 protocols.



application

A program or set of programs that performs a task; for example: payroll, inventory management, and word processing applications.



Application Development Client

An application development product that lets applications developed on a client workstation access remote database servers, including host relational databases, through the DB2 Connect products.



application ID

A unique string that is generated when an application connects to a database or when DB2 Connect receives a request to connect to a DRDA database. An identifier is generated when 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 name

The name of the application running on the client that identifies it to the database manager or DB2 Connect. The client passes the application name to the server to establish the database connection.



application programming interface (API)

A functional interface that allows an application program written in a high-level language to use specific data or functions of the operating system or another program, such as a database management system. In DB2, APIs enable most of the administrative functions from within an application 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 using the DRDA application-directed protocol.



application server

In DB2 for z/OS and OS/390, the target of a request from a remote application. In the DB2 environment, the distributed data facility (DDF) provides the application server function for accessing DB2 data from remote applications.



APPN

See [Advanced Peer-to-Peer Networking]
archived log

The set of log files that is closed and is no longer needed for normal processing. These files are retained for use in roll forward recovery.

See also [active log]


ASCII

See American National Standard Code for International Interchange.



AST

See [automatic summary table]
asynchronous

Without a regular time relationship; unpredictable with respect to the processing of program instructions.



asynchronous I/O

The nonsequential processing of read and write requests across multiple disks.



attach

To remotely access objects at the instance level.



authentication

The process of validating a supplied user ID and password against a security facility.



authority

A user's access and ability to perform high-level database management operations such as maintenance and utility operations. A user's authority level is used with privileges to control access to the database and its database objects.



authorization

The process by which DB2 obtains information about the authenticated user, such as the database operations the user may perform and which data objects the user may access.



authorization ID

A string that can be verified for connecting to a DB2 UDB and to which a set of privileges is applied. An authorization identifier can represent an individual, an organizational group, or a function, but the DB2 UDB does not determine this representation. The authorization ID is defined in an external security facility that DB2 supports.



autocommit

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



automatic configuration parameters

A set of configuration parameters whose values can be changed automatically by the database manager to reflect the current resource utilization.



automatic summary table (AST)

A summary table defined such that changes made to the underlying tables cascade to it immediately without the need for a REFRESH TABLE statement.



autonomic computing system

A computing system that manages, repairs, and protects itself.



AWE

See [Address Windowing Extensions]


Understanding DB2(R. Learning Visually with Examples)
Understanding DB2: Learning Visually with Examples (2nd Edition)
ISBN: 0131580183
EAN: 2147483647
Year: 2004
Pages: 313

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