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DL/I and CA IDMS/DB › Program Communication Blocks › Defining a PCB

Defining a PCB

Sample PCB

The example below shows the source statements for a sample PCB

 PCB     TYPE=DB,DBDNAME=DBDNEW,PROCOPT=G,
              KEYLEN=45,PROCSEQ=INDEX1
 SENSEG  NAME=SEGRT1,PARENT=0
 SENSEG  NAME=SEG3,PARENT=SEGRT1
 SENSEG  NAME=SEG4,PARENT=SEG3
 SENSEG  NAME=SEG2,PARENT=SEGRT1
 PSBGEN  LANG=COBOL,PSBNAME=PSB1
 END

Figure 18. Sample PCB definition

The PCB Statement

To define a PCB, you must first specify the PCB statement. On the PCB statement, the DBDNAME parameter identifies a physical or logical DBD from which to select segments. The PROCOPT parameter specifies a PROCOPT option for the entire database.

The KEYLEN Parameter

The KEYLEN parameter specifies the maximum key length to be used when the key (sequence field value) of a segment is concatenated with the keys of the higher-level segments in its hierarchical access path. The KEYLEN value is determined by adding up the lengths of the sequence fields necessary to reach the lowest-level segment in the hierarchy of available segments.

Sensitive Segment (SENSEG) Statements

The bulk of a PCB definition consists of SENSEG (sensitive segment) statements. Each SENSEG statement specifies a segment to be included from the named DBD. The SENSEG statement can also include a PROCOPT option for the segment.