To qualify a VSAM group-level key field, you write custom logic that moves the key elementary field values to a group-level qualification value field that you define. You then qualify the key with the qualification value field. You write and execute the custom logic at the Before DB Access event.
For example, suppose that a key has the following elementary fields.
01 SALES-KEY. 05 REGION-CODE PIC X(2). 05 YEAR-CODE PIC X(2).
You write the following logic at the Before DB Access event, on the DB Call Tailoring window. The logic defines a group-level Working-Storage field and moves the values of the two elementary fields to it.
MOVE SCREEN-REGION-CODE TO REGION-CODE MOVE SCREEN-YEAR-CODE TO YEAR-CODE WS01 NEW-SALES-KEY. 05 REGION-CODE PIC X(2). 05 YEAR-CODE PIC X(2).
Then, on the Qualification window, you qualify the key field, SALES-KEY, with the qualification value field, NEW-SALES-KEY.