Example 8: keyed-sequential update (KSDS, RRDS)

In this example, GET and PUT macros are used to retrieve and update fixed-length, 50-byte records. Records are updated synchronously in a work area. This example requires the use of a work area because you cannot update a record in the I/O buffer.

UPDATA  ACB    MACRF=(KEY,SEQ,                                         x
               OUT)
 
LIST    RPL    ACB=UPDATA,      UPD indicates the record may be stored x
               AREA=WORK,       back (or deleted).                     x
               AREALEN=50,                                             x
               OPTCD=(KEY,SEQ,                                         x
        .      SYN,UPD,MVE)
        .
LOOP    GET    RPL=LIST
 
        LTR    15,15
        BNZ    ERROR

Decide whether to update the record.

        BE     LOOP             Do not update it; retrieve another.

Update the record.

        PUT    RPL=LIST         Store the record back.
        LTR    15,15
        BNZ    ERROR
        B      LOOP
ERROR   ...                     Request was not accepted, or failed.
        .
 
WORK    DS     CL50             VSAM puts the retrieved record here.

A GET for update (OPTCD=UPD) must precede a PUT for update. Besides retrieving the record to be updated, GET positions VSAM at the record retrieved, in anticipation of the succeeding update (or deletion). It is not necessary for you to store back (or delete) the record you retrieved for update. VSAM's position at the record previously retrieved allows you to issue another GET to retrieve the following record. You cannot, however, store back the previous record: the position for update has been forgotten because of the following GET.