The below is the list on life cycle of COBOL indexed-files.
- Defining an indexed file
- Opening and closing indexed files
- Reading through a file
- Adding records to indexed files
- Looking up records in indexed files
- Changing records in indexed files
- Deleting records in indexed files
Defining indexed file:
DATA DIVISION. FILE SECTION. * FD VENDOR-FILE LABEL RECORDS ARE STANDARD. 01 VENDOR-RECORD. 05 VENDOR-NUMBER PIC 9(5). 05 VENDOR-NAME PIC X(30). 05 VENDOR-ADDRESS-1 PIC X(30). 05 VENDOR-ADDRESS-2 PIC X(30). 05 VENDOR-CITY PIC X(20). 05 VENDOR-STATE PIC X(2). 05 VENDOR-ZIP PIC X(10). 05 VENDOR-CONTACT PIC X(30). 05 VENDOR-PHONE PIC X(15).
Opening and closing of indexed files:
PROGRAM-BEGIN. OPEN OUTPUT VENDOR-FILE. CLOSE VENDOR-FILE.
..
PROCEDURE DIVISION. PROGRAM-BEGIN. OPEN I-O VENDOR-FILE. PERFORM MAIN-PROCESS. CLOSE VENDOR-FILE.
Reading through a file:
OPEN I-O VENDOR-FILE. READ VENDOR-FILE NEXT RECORD.
Adding records to indexed files:
WRITE-VENDOR-RECORD. WRITE VENDOR-RECORD INVALID KEY DISPLAY "RECORD ALREADY ON FILE".
Changing Records in Indexed files:
PERFORM ENTER-VENDOR-NUMBER. PERFORM READ-VENDOR-RECORD. IF RECORD-FOUND = "Y" PERFORM LOAD-NEW-VENDOR-DATA PERFORM REWRITE-VENDOR-RECORD. * READ-VENDOR-RECORD. MOVE "Y" TO RECORD-FOUND. READ VENDOR-FILE RECORD INVALID KEY MOVE "N" TO RECORD-FOUND. * REWRITE-VENDOR-RECORD. REWRITE VENDOR-RECORD INVALID KEY DISPLAY "ERROR REWRITING VENDOR RECORD".
Deleting a Record in Indexed files:
PERFORM ENTER-VENDOR-NUMBER. PERFORM READ-VENDOR-RECORD. IF RECORD-FOUND = "Y" PERFORM DELETE-VENDOR-RECORD. * READ-VENDOR-RECORD. MOVE "Y" TO RECORD-FOUND. READ VENDOR-FILE RECORD INVALID KEY MOVE "N" TO RECORD-FOUND. * DELETE-VENDOR-RECORD. DELETE VENDOR-FILE RECORD INVALID KEY DISPLAY "ERROR DELETING VENDOR RECORD".
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