FILE START Statement
FILE START Statement
START is used to set the file pointer to read the record. START won't retrieve any record and only sets the pointer before beginning a sequence of READ operations.
Points to note -
- The file should open in INPUT or I-O mode to perform the START statement.
- The START statement is used for indexed and relative files.
- A START statement is used when the ACCESS MODE is DYNAMIC.
Syntax -
START logical-file-name
[KEY IS {EQUAL TO | GREATER THAN | LESS THAN | NOT ...} ws-key-value]
[INVALID KEY statements-set1]
[NOT INVALID KEY statements-set2]
[END-START].
Note! All statements coded in [ ] are optional.
Parameters -
- logical-file-name - Specifies the file from where the positioning needs to be done.
- KEY IS - This clause is used to specify the position where the file pointer should be set. The key-value can be set to start from an exact match or from a greater or lesser value.
- END-START - An optional phrase that marks the end of the START statement. END-START is not required when a START statement ends with a period.
Error Handling -
- INVALID KEY - This phrase specifies the action to be taken when the START operation doesn't find a matching key value. The statements following INVALID KEY are executed in such cases. This is applicable to indexed or relative files.
- NOT INVALID KEY - when the START operation finds a matching key value. This is applicable to indexed or relative files.
Note! If the FILE-STATUS clause is coded, the associated file status is updated when the START statement is executed.
Practical Example -
Scenario - Start browsing the file from EMP-ID 'E0003'.
Input file -
BROWSE MATESY.EMPLOYEE.INPFILE Line 00000000 Col 001 080 Command ===> Scroll ===> CSR ----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 ********************************* Top of Data ********************************** E0001EMPLOYEE1 MANAGER 0000200000 E0002EMPLOYEE2 TL 0000150000 E0003EMPLOYEE3 SE 0000050000 E0004EMPLOYEE4 SSE 0000040000 E0005EMPLOYEE5 SE 0000045000 ******************************** Bottom of Data ********************************
Code -
----+----1----+----2----+----3----+----4----+
IDENTIFICATION DIVISION.
PROGRAM-ID. FILEBR.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT EMPFILE ASSIGN TO INPUT01
ORGANIZATION IS INDEXED
ACCESS MODE IS DYNAMIC
RECORD KEY IS EMP-ID
FILE STATUS IS WS-FS1.
DATA DIVISION.
FILE SECTION.
FD EMPFILE
RECORD CONTAINS 80 CHARACTERS
BLOCK CONTAINS 800 CHARACTERS
DATA RECORD IS EMPFILE-RECORD.
01 EMPFILE-RECORD.
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 WS-FS1 PIC 9(02).
05 WS-EOF-SW PIC X(01).
88 WS-EOF VALUE 'Y'.
88 WS-NOT-EOF VALUE 'N'.
PROCEDURE DIVISION.
* Opening file in INPUT mode
OPEN INPUT EMPFILE.
* Set the file pointer to read the record
MOVE 'E0003' TO EMP-ID.
START EMPFILE
KEY IS EQUAL TO EMP-ID
INVALID KEY DISPLAY "RECORD NOT FOUND"
NOT INVALID KEY PERFORM 1000-READ-EMPFILE
THRU 1000-EXIT
END-START.
* Closing file
CLOSE EMPFILE.
STOP RUN.
1000-READ-EMPFILE.
* Reading records sequentially using NEXT RECORD
* until end of the file
PERFORM UNTIL WS-EOF
READ EMPFILE
NEXT RECORD
AT END SET WS-EOF TO TRUE
NOT AT END DISPLAY EMPFILE-RECORD
END-READ
END-PERFORM.
1000-EXIT.
EXIT. Run JCL -
//MATESYF JOB MSGLEVEL=(1,1),NOTIFY=&SYSUID //* //STEP01 EXEC PGM=FILEBR //STEPLIB DD DSN=MATESY.COBOL.LOADLIB,DISP=SHR //INPUT01 DD DSN=MATESY.EMPLOYEE.INPFILE,DISP=SHR //SYSOUT DD SYSOUT=*
Output -
E0003EMPLOYEE3 SE 0000050000 E0004EMPLOYEE4 SSE 0000040000 E0005EMPLOYEE5 SE 0000045000