Merging records

The sample COBOL program in Figure 1 calls DFSORT to merge the presorted bookstore master file (MASTER-FILE) with another presorted file (NEW-BOOKS-FILE) to create a new master file (MERGED-FILE).

The JCL for the program is as follows:

//EXAMP    JOB  A492,PROGRAMMER
//BOOKS    EXEC PGM=COBOLP
//STEPLIB  DD   DSN=USER.PGMLIB,DISP=SHR
//SYSOUT   DD   SYSOUT=A
//MASTERFL DD   DSN=A123456.MASTER,DISP=OLD
//NEWBOOKS DD   DSN=A123456.NEW,DISP=OLD
//MERGEDFL DD   DSN=A123456.OUTC,DISP=(NEW,CATLG,DELETE),
//           SPACE=(CYL,(1,1)),UNIT=SYSDA

Figure 1 shows the sample COBOL program.

Figure 1. Sample COBOL Program with MERGE Commands

 IDENTIFICATION DIVISION.
 PROGRAM-ID.
     COBOLP.
 ENVIRONMENT DIVISION.
 INPUT-OUTPUT SECTION.
 FILE-CONTROL.
     SELECT SD-FILE ASSIGN TO
     DUMMYNM.
     SELECT MASTER-FILE ASSIGN TO
     MASTERFL.
     SELECT NEW-BOOKS-FILE ASSIGN TO
     NEWBOOKS.
     SELECT MERGED-FILE ASSIGN TO
     MERGEDFL.
 DATA DIVISION.
 FILE SECTION.
 SD  SD-FILE
     DATA RECORD IS SD-RECORD.
 01  SD-RECORD.
  05 TITLE-KEY  PICTURE X(75).
  05 FILLER     PICTURE X(98).

 FD  MASTER-FILE
     DATA RECORD IS MASTER-RECORD.
 01  MASTER-RECORD.
  05 FILLER     PICTURE X(173).

 FD  NEW-BOOKS-FILE
     DATA RECORD IS NEW-BOOKS-RECORD.
 01  NEW-BOOKS-RECORD.
  05 FILLER    PICTURE X(173).

 FD  MERGED-FILE
     DATA RECORD IS MERGED-RECORD.
 01  MERGED-RECORD.
  05 FILLER    PICTURE X(173).
  .
  .
  .

 PROCEDURE DIVISION.
  .
  .
  .

 MERGE-ROUTINE SECTION.
     MERGE SD-FILE
     ASCENDING KEY TITLE-KEY
     USING MASTER-FILE NEW-BOOKS-FILE
     GIVING MERGED-FILE.
     IF SORT-RETURN > 0
     DISPLAY "MERGE FAILED".
     STOP RUN.