CICS-Sequential and Random Access

Not only in CICS, in any of the mainframe Technologies, reading of the files can be done in multiple ways.

Sequential &
Random Access

Especially in CICS, Sequential and Random access are most popular ways of reading files.

Sequential Access: STARTBR (start browse) keeps record at the key position, from where we want to read a record.

READNEXT-will actually read the record into working storage file description area.

Sample syntax:

EXEC CICS STARTBR
   DATASET('FILEAA')
   RIDFILD(REC-IO-KEY)==> Record Key
  GTEQ
END-EXEC.

—-

EXEC CICS READNEXT
   DATASET('FILEAA')
    INTO(FILE-IO-AREA) ==working storage file description at '01' level
   RIDFILD(REC-IO-KEY)==>Record Key
   GTEQ
END-EXEC.

Random Access: File reading by this way will be achieved with “READ” command. It reads the record, as per key mentioned, and moves into working storage record area.

Sample syntax:

EXEC CICS READ
   DATASET('FILEAA')
    INTO(FILE-IO-AREA) ==working storage file description at '01' level
   RIDFILD(REC-IO-KEY)==>Record Key
   GTEQ
END-EXEC.

These may look simple, but, many people do not have much idea. I am sure it will help you.

In my next posts, I will give how data will be retrieved by using DB2 and IMSDB.

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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.