IMS DB- Why PCBs Must Give In Sequence In ENTRY

As we all know, PSB is a database, it represents database view to the application program. And, PSBs are combination of various PCBs. So each PCB represents to one segment.

In the PSB generation, we can code in PCB blocks of sensitive segments and sensitive fields. To run each batch program , we need to supply Program-name and PSB-name in JCL thru Parm parameter.

PARM=(DLI, Program-name,PSB-name,,,).

Very important points to remember are just read the below bullet ones:

  • In the Entry DLITCBL USING PCB1

PCB2,  the PCB masks must be in sequence of PSB. Since, entry statement uses PCBs as per address. If we do not give PCBs as per sequence your program will abend.

  • If we use multiple sub-programs in an IMS program, only in the main program we have to give ENTRY DLITCBL  statement-NOT needed in the sub-programs.
  • One PSB is enough(normally we supply it in the JCL) even all the sub-programs in the main-program are IMS programs.
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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.