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D

data

Facts and numbers that can be collected and processed. The processing of data yields information that is meaningful to an organization.

data access passkey

In CA ICMS, a passkey that allows access to objects. See also catalog access passkey.

data area

See table data area.

data characteristic table (DCT)

In CA IDMS Presspack, a table that contains either customized or generic information on data. The table is used to optimize record and table compression and decompression.

data communications administrator (DCA)

The individual and/or staff responsible for implementing and maintaining the DC/UCF system.

Data Definition Language (DDL)

The statements that define the logical and physical components of a CA IDMS/DB database definition (that is, the SQL schema or non-SQL schema, DMCL, subschema, and database name table). DDL is also used for Data Description Language and the terms are interchangeable. See Data Description Language (DDL).

Data Description Language (DDL)

The statements that define the logical and physical components of CA IDMS/DB database definition (that is, the SQL schema or non-SQL schema, DMCL, subschema, and database name table). DDL is also used for Data Definition Language and the terms are interchangeable. See Data Definition Language (DDL).

data dictionary

See dictionary.

data dictionary administrator (DDA)

The individual and/or staff responsible for implementing and maintaining the data dictionary.

Data Dictionary Definition Language (DDDL)

The IDD statements used to define the contents of the data dictionary.

data dictionary reports utility

See IDMSRPTS utility.

data dictionary schema

The schema (IDMSNTWK) that describes the data dictionary database.

data field

In the Mapping Facility, a map field that displays the value (if any) of a record element associated with the map field and, optionally, allows the terminal operator to input data.

data flow diagram (DFD)

A diagram that shows the flow of data to and from a particular function or set of functions. Data flow diagrams are used during the logical phase of database design.

data item

See attribute, element.

Data Manipulation Language (DML)

Statements by which application programs access and manipulate the contents of a CA IDMS/DB database. DML statements can be coded in COBOL, PL/I, and Assembler application programs. See also path-DML commands, navigational DML, SQL DML.

data model

The theoretical basis of a database system.

data security

The protection of data against accidental or intentional disclosure to unauthorized persons, unauthorized modifications, or destruction.

data services interface (DSI)

An interface between an application requesting CA IDMS services and the component providing the services. If necessary the DSI layer will use the data communications architecture for forwarding requests to a separate address space or remote node.

data sharing

The CA IDMS feature that allows multiple CA IDMS central versions to share update access to the same database areas. This feature requires the IBM Parallel Sysplex environment.

Data Sharing Group

A named collection of CA IDMS systems in an IBM parallel sysplex environment. CA IDMS systems that participate in a Data Sharing Group may share update access to a database, broadcast commands to all members of the group, share queues and enqueue common resources, and monitor and report on all members of the Data Sharing Group.

data structure diagram

A graphic representation that illustrates the components and relationships within a database, including records, sets, and areas. See also record-type diagram.

data table

Presentation of data as a series of rows and columns. A data table can be manipulated with the three relational operations: select, project, and join. In CA IDMS/DB, a data table can be physically stored in the database or it can be a view of other tables in the database. See also table, view.

data transfer services (DTS)

A component of the CA IDMS database communications architecture that calls the name server to determine the location of the target resource and, if necessary, forwards the request to the distributed node services (DNS) component for routing.

data type

A set of values that share processing characteristics. For example, the set of all integers is a data type.

database

A storage facility in which all data is centralized and arranged independently of applications; a named collection of data tables.

database administrator (DBA)

The individual and/or staff responsible for implementing and maintaining the database.

database analysis utility

See IDMSDBAN utility.

database buffer

The storage space in memory that holds database pages while CA IDMS/DB accesses information on those pages. You define a buffer as part of the DMCL. Each buffer is associated with one or more database files. See also buffer, journal buffer, and record buffer.

database function

Services requested by application programs and performed by the DBMS to access and maintain the database.

database I/O

The input/output operations performed by the DBMS on the physical database.

database key (db-key)

A unique identifier assigned by CA IDMS/DB to each record occurrence when it is stored in the database. The database key consists of the record's database page number and line index.

database management system (DBMS)

The software component that performs the physical database access, handling all database input/output and space management functions.

database name

An entity that identifies the segments to be accessed as part of the logical database. One or more database names comprise a database name table.

database name table

An entity associated with a DMCL that is used at runtime to map the logical database definition to one or more segments in the DMCL. The definition of a database name table includes one or more database names.

database node

The node name of the DC/UCF system.

database page

See page.

database procedure

In CA IDMS/DB, a special-purpose subroutine designed to perform predefined programming functions, such as data compression or data validation. The DBMS invokes a database procedure according to a record's schema definition.

database record

A group of related data fields defined in a non-SQL schema and stored in a CA IDMS/DB database. Database records function as the building blocks of logical records.

database resource

Within centralized security, an entry associated with the definition or access to a database. See also global resource, system resource.

database session

An association between an application and a CA IDMS database that can be used to retrieve and update data.

database status code

See status code.

database transaction

A database transaction is a unit of recovery representing work done by one or more database sessions. All access to CA IDMS data from within a database session is done under the control of a database transaction. See also database session, local transaction, distributed transaction, transaction branch.

database-key format

The structure of the database keys that identify the records in a given database. A segment of a database can have only one database-key format. A database key is a 32-bit field that contains two values: the record's page number and its line index. The page number can occupy 20 through 30 bits of the database key. The line index can occupy 2 through 12 bits of the database key. A synonym for database-key format is radix.

db-key

See database key (db-key).

DBA

See database administrator (DBA).

DBA group

In CA ICMS, a catalog-foundation group entity whose members share administrative authority over the catalog.

DBAK checkpoint

A journal checkpoint that marks the abnormal completion of a distributed transaction. A DBAK checkpoint is written to the initiator's journal file during the first phase of a two-phase commit operation as soon as it determines that the transaction's changes should be backed out. A DBAK checkpoint is written to a participant's journal file when it is informed that its changes should be backed out. See coordinator, participant, and two -phase commit.

DBCS

See double-byte character set (DBCS).

DBGROUP

A named collection of central versions that provide access to a common set of data. A DBGROUP is used in conjunction with dynamic database routing to facilitate load balancing in a parallel sysplex environment. A central version is a group member if the DBGROUP is defined in the system's database name table. See dynamic database session routing.

DBMS

See database management system (DBMS).

DBNAME

See database name.

DBNODE

See database node.

DBTBGEN macro

A macro used by online debugger to assign activity numbers to online debugger functions.

DC system

A database/data communications system that includes CA IDMS/DB and CA IDMS/DC.

DC/UCF nucleus

See nucleus.

DC/UCF system

A general term for a system that is either a CA IDMS/DC system or a CA IDMS UCF system. A DC/UCF system provides both database and data communications services.

DC/UCF system reports

See CREPORTs.

DCA

See data communications administrator (DCA).

DCE

See dispatch control element (DCE).

DCMT task

A system task that invokes a DC master terminal (DCMT) function. DCMT functions are used to monitor and control various aspects of the DC/UCF system at runtime.

DCOM checkpoint

A journal checkpoint that marks the successful completion of a distributed transaction. A DCOM checkpoint is written to the initiator's journal file at the start of the second phase of a two-phase commit operation. A DCOM checkpoint is written to a participant's journal file when it is informed that its changes should be committed. See also coordinator, participant, and two-phase commit.

DCPROFIL task

A system task that displays system information, such as installation options, system resource usage, the system exits used, the ADSO and OLQ configurations, and the optional APARs currently applied.

DCSYSTEM

The name that, when combined with a version number, uniquely identifies an occurrence of a system added to the data dictionary through the system-generation compiler.

DCT

See data characteristic table (DCT).

DCUF task

A system task that invokes a DC/UCF user function. User functions perform support services for the terminal user at runtime, such as sending messages or altering profile information.

DDA

See data dictionary administrator (DDA).

DDDL

See Data Dictionary Definition Language (DDDL).

DDDL compiler

An IDD-supplied program that stores DDDL descriptions in the data dictionary.

DDL

See Data Description Language (DDL).

DDLCAT dictionary area

A dictionary area that contains definitions of physical databases (segments, DMCLs, and database name tables); at sites with the SQL option, contains definitions of SQL entities (tables, constraints, indexes, and so on).

DDLCATLOD dictionary area

A dictionary area that contains DMCL load modules, database name table load modules, and access modules at sites with the SQL option.

DDLCATX dictionary area

A dictionary area that contains indexes defined on entities stored in the DDLCAT area.

DDLDCLOD area

A dictionary area that contains load modules associated with entities contained in the DDLDML area; for example map load modules, subschema load modules, and dialog load modules. See also load area.

DDLDCLOG area

The log runtime area. The log area contains central version log records when the log file for the central version is assigned to the database. See also log, log file.

DDLDCMSG area

The message area of the data dictionary. The DDLDCMSG area contains message text identified by a message id. The area contains messages loaded at installation as well as user messages added through the DDDL compiler.

DDLDCRUN area

The queue runtime area. The DDLDCRUN area contains the queue work records used by CA-supplied tools and online user programs.

DDLDCSCR area

The central version scratch runtime area. The DDLDCSCR area contains scratch work records used for temporary storage of data that can be accessed by CA-supplied tools and online user programs.

DDLDML area

The area of the dictionary that contains definitions of DC/UCF systems, non-SQL schemas and subschemas, maps, dialogs, source modules, records and elements, IDD users, and classes and attributes.

DDLOCSCR area

The local mode scratch area that contains runtime scratch records used by CA-supplied tools and user programs issuing SQL requests in local mode.

DDLSEC area

The runtime area that contains user and group information.

DDS line

A communication line that allows one DC/UCF system to communicate with another. See also communication line.

DDS network

Multiple DC/UCF systems connected by CA IDMS SVCs or DDS lines.

DDS node

A DC/UCF system that participates in a CA IDMS DDS network. See also host node, target node, local node, and node.

deadlock

An unresolvable contention for the use of resources.

deadlock prevention element (DPE)

Under DC/UCF, the control block used to detect deadlock situations.

debug local block (DLB)

The control block used in a debugging session.

debugger

The online facility used to detect, trace, and resolve programming errors in programs that operate in a DC/UCF environment.

declaration module

In the CA ADS dialog compiler, a module used under the SQL option to declare cursors and to issue global WHENEVER statements. The statements in a declaration module are not executed. They are compiler directives used by the CA ADS dialog compiler at dialog compilation.

decompression

The process of expanding compressed data. To decompress a database record, you use CA IDMS Presspack or the IDMSDCOM database procedure. See also compression.

default

A preset value for a given option. A default value is used automatically unless an overriding value is explicitly specified.

default access module

The access module associated with the application program issuing the first SQL statement executed within the SQL session. See also access module.

default dictionary

The dictionary accessed by CA IDMS tools if you do not specify a dictionary by other means such as using a DCUF SET DICTNAME command or CONNECT statement. To define a default dictionary to the runtime environment, include a subschema mapping in the database name table associated with the runtime DMCL for the IDMSNWK subschemas.

default ready mode

A default ready mode for an area specified in a subschema definition. The default mode determines the mode in which the area is to be readied for programs using that subschema. Therefore, the programs do not need to issue a READY command for the area. However, if the program issues a READY command for one area, it must issue a READY command for all areas to be accessed.

definition area

See table definition area.

definition privilege

Under centralized security, a privilege that allows a user to manipulate the definition of certain resources. See also access privilege, administration privilege.

DELETE statement

1) An SQL database access statement that deletes one or more rows from a table. 2) A DDDL command that removes one or more entity definitions from the dictionary.

derivation

The process of creating a view of data tables in the database. See also data table, view.

described statement

A dynamically-compiled SQL statement for which the SQLDA contains information.

destination

An IDD entity type used to document groups of users or logical terminals as a single logical destination within a teleprocessing system.

detail area

The portion of a pageable map that is located across the middle of the screen. The fields in the detail area define the detail occurrences for that map.

detail occurrence

On a pageable map, each occurrence of the set of map fields defined in the detail area. The runtime system determines how many detail occurrences of this set of fields can fit in the detail area of each page.

development center

An organizational structure, typically within an MIS department, geared toward the development of high-speed, high-volume production applications.

DFD

See data flow diagram (DFD).

DFGT checkpoint

A journal checkpoint that marks the end of a distributed transaction. It is written to a coordinator's or participant's journal file at the end of a two-phase commit operation, but only if some other distributed checkpoint (DCOM, DBAK, DIND, or DPND) had previously been written for the transaction.

dialog

In CA ADS, an executable module that performs a unit of work in an application. A dialog is constructed from other modules, such as subschema map, and process module definitions. A dialog typically handles all processing associated with a given online transaction. This includes accessing and updating the database and handling mapout and mapin operations.

dialog components

The premap process module, response process modules, map, and subschema that make up a dialog. Components are associated with the dialog during a dialog compiler session.

dialog function

In CA ADS, an application function associated with a dialog. The dialog performs the processing work required by the function. For example, the dialog for an employee update function retrieves and updates employee records in the database.

Most functions in a typical CA ADS application are dialog functions. See also application function, dialog.

dialog response process

See response.

dialog work record

Dictionary records that are directly associated with a CA ADS or CA ADS Batch dialog. Dialog work records can be used as working storage during processing. See also map work record.

dictionary

The central repository used by CA IDMS products for data definitions, modules, documentation, and runtime information. The dictionary itself is a CA IDMS/DB database. See also ASF dictionary, default dictionary, session default dictionary, system dictionary.

dictionary name

The name of the dictionary being accessed.

dictionary node

In your DC/UCF communications network, the logical name of the DC/UCF system that controls the data dictionary being used.

DICTNAME

See dictionary name.

DICTNODE

See dictionary node.

DIND checkpoint

A journal checkpoint written to a participant's journal file to note that it is prepared to commit its portion of a distributed transaction. The participant will wait for a directive from the coordinator as to whether to complete the commit operation or to back out changes. See also coordinator, participant, and two-phase commit.

DIRECT location mode

In CA IDMS/DB, the location mode that permits the user to suggest the actual database page on which a record will be placed.

directory load utility

See IDMSDIRL utility.

DISCONNECT

The database access function that removes a member record occurrence from a set but does not delete the record from the database. DISCONNECT can only be issued for a record that is defined as an optional member of a particular set.

dispatch control element (DCE)

The DC/UCF control block that is used to manage the dispatching of tasks.

displacement

In CA IDMS/DB, a storage method in which records are clustered a specified distance away from their owner records. Displacement can be used for both VIA set member records and bottom-level index (SR8) records.

Distributed Database System (DDS)

See CA IDMS DDS.

distributed node services (DNS)

A component of the CA IDMS communications architecture that manages communications for remote data access.

distributed transaction

A transaction in which changes are made to resources controlled by multiple resource managers.

distributed transaction identifier (DTRID)

A 16-byte value that uniquely and globally identifies a distributed transaction. A DTRID is composed of an 8-byte node name and an 8-byte hexadecimal value.

DLB

See debug local block (DLB).

DMCL module

The module that relates the logical structure of the database to the physical files on which it resides. The DMCL describes a CA IDMS/DB runtime environment. It includes segment, journal, and buffer definitions and identifies the database name table that the DBMS uses at runtime to map a schema definition of the database to specific segments.

DMCL Syntax Generator

A program, IDMSDMCC, that generates release 12.0 physical database definitions from validated release 10.2 DMCL and schema definitions.

DML

See Data Manipulation Language (DML).

DML precompiler

A compiler that converts DML statements in the source program to host language statements, producing a source file that serves as input to the host language compiler. For example, a COBOL program with embedded navigational or SQL DML statements is submitted first to the DMLC precompiler and then to the ANSI COBOL compiler.

DMLA

The DML precompiler for Assembler programs.

DMLC

The DML precompiler for COBOL programs.

DMLP

The DML precompiler for PL/I programs.

domain

In CA IDMS/DB, the possible values for a particular column in a table; for example, the 50 2-character state codes). See also security domain.

domain constraint

A constraint that restricts column values. A column's data type restricts values to the data type of the column. A check constraint restricts column values to a range of values that satisfies a search condition.

domain integrity

In CA IDMS/DB, the data integrity rule that enables users to define a set of valid values for a particular column in a data table.

double-byte character set (DBCS)

A 16-bit (double-byte) character set that allows representation of a large set of graphic characters on the appropriate hardware. With DBCS, it is possible to build applications for Japanese, Chinese, and Korean users.

download

The transfer of data from CA ICMS to a personal computer or minicomputer.

DPE

See deadlock prevention element (DPE).

DPND checkpoint

A journal checkpoint that marks an interim result for a distributed transaction. A DPND checkpoint may be written for several reasons, such as when a participant is forced to heuristically complete a transaction or when a coordinator is unable to communicate with one or more of its participants. See also coordinator, participant, and two-phase commit.

DREPORTs

Reports that provide information on entities stored in the DDLDML area of the dictionary.

DTRID

See distributed transaction identifier.

duplicate names

Identical names assigned to two or more catalog entities.

duplicates options

In a non-SQL schema, the options that determine how record occurrences with duplicate key values are stored.

duration

In the SQL option, a value that represents a time interval. These can be: labeled durations, which represent a specific unit of time (for example, 10 MINUTES represents 10 minutes); date duration, which denotes an interval of years, months, and days; and time duration, which represents an interval of hours, minutes, and seconds.

dynamic database session routing

A feature that allows the dynamic selection of the node to which a database session is to be connected. The selection is made by determining which CV in the DBGROUP has the CPU cycles available to service the request. This feature requires the IBM Parallel Sysplex environment and must be used in conjunction with the Data Sharing feature in order to dynamically route update requests. See also DBGROUP.

dynamic program definition

The process of defining a program to DC/UCF at runtime through a DCMT VARY DYNAMIC PROGRAM command. The definition exists only for the current execution of the system.

dynamic SQL

An SQL statement that is not known to the program at precompile time and therefore is compiled dynamically when the program executes.

dynamic system monitor

An online facility that allows you to examine DC/UCF system activity based on a time interval. The dynamic system monitor is invoked by the task code OPER.

dynamic task definition

The process of defining a task to the DC/UCF system at runtime by means of the DCMT VARY DYNAMIC TASK command. The definition exists only for the current execution of the system.