REWRITE

The REWRITE command updates a record in a file. Unlike WRITE, which adds a new record, REWRITE replaces the contents of a record that is already there. It is the second half of the classic read-for-update pattern.

Syntax of the REWRITE command

• FILE - the name of the file that contains the record to be updated. This name must be defined in the File Control Table (FCT).
• FROM - the data area that contains the updated record to be written back.
• REWRITE has no RIDFLD option. CICS already knows which record to update because you read it with the UPDATE option first.

The read-for-update pattern

• Before you issue REWRITE, you must issue a READ command with the UPDATE option for the same record. The UPDATE read holds the record for your task.
• Change the fields you need in the record area, then issue REWRITE with the FROM option pointing at the same area.
• You cannot change the value of the primary key with REWRITE. If you try, the INVREQ exceptional condition occurs. To change a key, delete the old record and write a new one.
• Example:-
  
  EXEC CICS READ FILE('CUSTMAS') INTO(CUSTOMER-MASTER-RECORD) RIDFLD(CM-CUSTOMER-NUMBER) UPDATE RESP(RESPONSE-CODE) END-EXEC. IF RESPONSE-CODE = DFHRESP(NORMAL) ADD 1 TO CM-ORDER-COUNT EXEC CICS REWRITE FILE('CUSTMAS') FROM(CUSTOMER-MASTER-RECORD) RESP(RESPONSE-CODE) END-EXEC IF RESPONSE-CODE NOT = DFHRESP(NORMAL) PERFORM 9999-TERMINATE-PROGRAM END-IF END-IF.