COBOL Updating a Record in Variable Length Indexed File Example

File Rewrite Tutorial   

Scenario - Reduce the salary 5000 for the employee id = E0005 in variable length KSDS file.

Input file -

Browse           MATEPK.EMPL.VKSDS                                 Top of 5    
Command ===>                                                       Scroll CSR  
                            Type KSDS     RBA                      Format CHAR 
Key                                          Col 1
<===>----10---+----2----+----3----+----4----+----5----+----6----+----7----+----
****  Top of data  ****
E0001EMPLOYEE1      MANAGER   0000200000         EMPLOYEE RECORD 1
E0002EMPLOYEE2      TL        0000150000         EMP REC 2
E0003EMPLOYEE3      SE        0000050000         EMP 3
E0004EMPLOYEE4      SSE       0000040000
E0005EMPLOYEE5      SE        0000040000         EMP 5
****  End of data  ****

Code -

----+----1----+----2----+----3----+----4----+----5----+
       IDENTIFICATION DIVISION.
       PROGRAM-ID. INDVFLUD.
       AUTHOR. MTH.

       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
      * EMPFILE Definition
           SELECT EMPFILE ASSIGN TO INPUT01
           ORGANIZATION IS INDEXED
           ACCESS MODE  IS RANDOM 
           RECORD KEY   IS EMP-ID
           FILE STATUS  IS WS-FS1.

       DATA DIVISION.
       FILE SECTION.
      * EMPFILE structure definition
       FD EMPFILE
           RECORD VARYING FROM 40 TO 80 CHARACTERS
                  DEPENDING ON EMPREC-LEN.
      * EMPFILE record structure definition
       01 EMP-RECORD80.
          05 EMP-ID        PIC X(05).
          05 EMP-NAME      PIC X(15).
          05 EMP-DESG      PIC X(10).
          05 EMP-SALARY    PIC 9(10).
          05 FILLER        PIC X(40).

       WORKING-STORAGE SECTION.
       01 WS-VAR.
          05 EMPREC-LEN    PIC 9(02).
          05 WS-FS1        PIC 9(02).

       PROCEDURE DIVISION.
      * Opening EMPFILE for reading
           OPEN I-O EMPFILE.

      * Readng a record randomly from the EMPFILE
           ACCEPT EMP-ID.
           READ EMPFILE
                    INVALID KEY DISPLAY "Record not found"
                NOT INVALID KEY PERFORM 1000-UPDATE-REC
                                   THRU 1000-EXIT
           END-READ.

      * Closing EMPFILE
           CLOSE EMPFILE.
           STOP RUN.
 
       1000-UPDATE-REC.

           COMPUTE EMP-SALARY = EMP-SALARY - 5000
           REWRITE EMP-RECORD80.

       1000-EXIT.
            EXIT.

Run JCL -

//MATEPKF  JOB MSGLEVEL=(1,1),NOTIFY=&SYSUID    
//*
//STEP01  EXEC PGM=INDVFLUD
//STEPLIB  DD  DSN=MATEPK.COBOL.LOADLIB,DISP=SHR
//INPUT01  DD  DSN=MATEPK.EMPL.VKSDS,DISP=SHR
//SYSOUT   DD  SYSOUT=*
//SYSIN    DD  *
E0004
/*

File After Update -

Browse           MATEPK.EMPL.VKSDS                                 Top of 5    
Command ===>                                                       Scroll CSR  
                            Type KSDS     RBA                      Format CHAR 
Key                                          Col 1 
<===>----10---+----2----+----3----+----4----+----5----+----6----+----7----+----
****  Top of data  ****
E0001EMPLOYEE1      MANAGER   0000200000         EMPLOYEE RECORD 1
E0002EMPLOYEE2      TL        0000150000         EMP REC 2
E0003EMPLOYEE3      SE        0000050000         EMP 3
E0004EMPLOYEE4      SSE       0000035000
E0005EMPLOYEE5      SE        0000040000         EMP 5
****  End of data  ****

Explaining Example -

In the above example:

  • Variable length KSDS (MATEPK.EMPL.KSDS) file is used as an input file.
  • File organization is INDEXED and accessing mode should be RANDOM.
  • It reads the record with the employee ID "E0004" dynamically. If the read is successful, it updates the salary for the record.