IPSB Compiler › PCB SECTION › PCB Statement

PCB Statement

A PCB statement is composed of entries from DL/I DBD and PCB statements. The DBD statement is located in the DBD, while the PCB statement is located in the PSB.

Syntax

►►─── PCB SECTION ─── . ─────────────────────────────────────────────────────►

 ►─┬────────────────────────────────────────────────┬────────────────────────►
   └─ PCB ACCESS METHOD is ──┬─ HDAM ────────────┬──┘
                             ├─ HIDAM ───────────┤
                             ├─ HISAM ───────────┤
                             ├─ INDEX ───────────┤
                             ├─ SECONDary index ─┤
                             └─ HSAM ────────────┘

 ►─┬───────────────────────┬─────────────────────────────────────────────────►
   └─ DBDNAME is dbd-name ─┘

 ►─┬──────────────────────────────────────────────┬──────────────────────────►
   └─ PROCessing OPTions are(is) ─── dl1-option ──┘

 ►─┬───────────────────────────────────┬─────────────────────────────────────►
   └─ POSitioning is ─┬─ SINGLE ◄──┬───┘
                      └─ MULTIPLE ─┘

 ►─┬─────────────────────────────────────────────────────────────────┬───────►◄
   └─ PROCessing SEQuence ──┬─ SET is indexed-set-name ──────┬─── . ─┘
                            └─ INDEX is indexed-field-name ──┘

Parameters

PCB SECTION.

PCB SECTION must be the first entry in this section, followed by as many PCB statements as required to define all hierarchical views referenced by the DL/I application.

Each PCB statement must be followed by SEGMENT statements to identify the segments that participate in the hierarchical view.

A PCB statement, in conjunction with subsequent SEGMENT statements, represents one DL/I hierarchical view. In addition to presenting the hierarchical view, the SEGMENT statement defines the relationships between the named segment and other DL/I segments, as represented by the corresponding CA IDMS/DB records and set relationships.

PCB ACCESS METHOD is

Specifies the DL/I access method by which the root segment in this database is accessed.

To determine the appropriate entry for this clause:

• First decide if ACCESS METHOD IS SECONDARY INDEX is appropriate (see below). If this entry is inappropriate, locate the DBD specified in the DBDNAME parameter of the DL/I PCB statement.
• Next, locate the DBD statement and use the value in the ACCESS parameter for the PCB ACCESS METHOD clause.

If the PCB specifies a logical database and if the SECONDARY INDEX entry is inappropriate:

• Locate the SEGM statement defining the root segment of the logical database. The SOURCE parameter in this SEGM statement references the source segment (first entry) and the physical database containing the source segment (second entry).
• Locate the DBD that defines this physical database.
• Use the ACCESS parameter value in its DBD statement.

Specific guidelines for the options of the PCB ACCESS METHOD clause follow:

HDAM

Specifies an HDAM access method. If this entry is specified, omit the PROCESSING SEQUENCE clause (see below).

HIDAM

Specifies a HIDAM access method. If this entry is specified, a PROCESSING SEQUENCE INDEX clause (see below) must be included.

HISAM

Specifies a HISAM access method. If this option is specified, a PROCESSING SEQUENCE SET clause (see below) must be included to name the relevant indexed set.

INDEX

Specifies an index access method. If this option is specified, a PROCESSING SEQUENCE SET clause must be included to name the relevant indexed set.

SECONDary index

Specifies a secondary index access method. If this option is specified, a PROCESSING SEQUENCE INDEX clause must be included to name the relevant indexed field.

PCB  TYPE=DB,DBDNAME=DBA,PROCOPT=A,KEYLEN=46,PROCSEQ=INDEX1

HSAM

Specifies an HSAM access method. If the root segment of the HSAM database is sequenced (that is, a sequenced HSAM), a PROCESSING SEQUENCE SET clause must be included. If the root segment of the HSAM database is unsequenced, omit the PROCESSING SEQUENCE clause. Although the HSAM access method is supported, consider each sequenced HSAM as a HISAM database when defining DL/I databases in the schema (see DL/I and CA IDMS/DB).

DBDNAME IS dbd-name

Specifies the name of the DL/I DBD associated with the database view being defined. This name corresponds to the DBD name found in the PCB mask in the application program. Use the name specified in the DBDNAME parameter of the PCB statement.

PROCessing OPTions are (is)

Specifies the DL/I processing options selected for this database view.

Processing options specify whether the DL/I application program can only read the segments in the database view or can both read and update the segments. If updating is allowed, the processing options also specify what kind of updating is permissible. You should include the processing options specified in the associated PROCOPT parameters of the DL/I PCB statement and its associated SENSEG statements.

dl1-option

Acceptable values for dl1-option are as follows:

 Value            Explanation

  G               The application program can read the segments.

  I               The application program can insert segments.

  R               The application program can read and replace
                  segments.

  D               The application program can read and delete
                  segments.

  A               The application program can read, insert, replace,
                  and delete segments.

  P               The application program can issue path calls.

A maximum of four options can be specified for each PCB statement. If more than one processing option is specified, do not separate the option by commas or blanks. See the appropriate DL/I documentation for details on DL/I processing options.

CA IDMS DLI Transparency requires that all processing options be specified for the PCB and does not permit any overrides of global options for an individual segment. To accommodate this requirement, you must enter in the PROCESSING OPTIONS clause the most inclusive DL/I processing option entered in the PSB's PCB statement and its SENSEG statements. If, for example, a PCB statement has PROCOPT=G, and three of the subsequent SENSEG statements have PROCOPT values of I, R, and A, respectively, you would enter the following:

PROCESSING OPTION IS A

By using the CA IDMS/DB access restrictions, you can restrict the type of access overrides/ for specific records and duplicate DL/I overrides of global processing options.

Note: For more information about CA IDMS/DB access restrictions, see the CA IDMS Database Administration Guide.

POSitioning is SINGLE/MULTIPLE

Specifies whether the interface is to maintain single or multiple positioning for this PCB. (Refer to the appropriate DL/I documentation for details on single and multiple positioning.) The default is SINGLE. The entry for the POSITION IS clause is found in the POS parameter of the DL/I PCB statement.

PROCessing SEQuence

The format of the PROCESSING SEQUENCE clause and whether it is included is determined by the access method specified in the PCB ACCESS METHOD clause above.

Omit the PROCESSING SEQUENCE clause if an HDAM access method is specified or if the database is an unsequenced HSAM.

SET is indexed-set-name

Include a PROCESSING SEQUENCE clause and specify the SET option if a HISAM or INDEX access method is specified or if the database is an HSAM database with a sequenced root segment. Then, include an indexed-set-name parameter.

Indexed-set-name is the 1- to 16-character name of the indexed set having as its member the record equivalent of the root segment of the HISAM, index, or sequenced HSAM database.

INDEX is indexed-field-name

Indexed-field-name identifies the index through which the root segment for this hierarchy view can be accessed.

Include the PROCESSING SEQUENCE clause and specify the INDEX option if a HIDAM or SECONDARY INDEX access method is specified. Then, include an indexed-field-name parameter.

Indexed-field-name is the 1- to 8-character name of the index. Make sure that the entry in this parameter is defined in the INDEX SECTION.