Compaq COBOL AAQ2G1FTK - Manual (Page 211)

Processing Files and Records
6.3 Creating and Processing Files
Example 6–25 (Cont.) Creating a Relative File in Random Access Mode
IDENTIFICATION DIVISION.
PROGRAM-ID. REL03.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT FLAVORS ASSIGN TO "BRAND"
ORGANIZATION IS RELATIVE
ACCESS MODE IS RANDOM
RELATIVE KEY IS KETCHUP-MASTER-KEY.
DATA DIVISION.
FILE SECTION.
FD
FLAVORS.
01 KETCHUP-MASTER.
02
FILLER PIC X(14).
02 REC-NUM PIC 9(05).
02 FILLER PIC X(31).
WORKING-STORAGE SECTION.
01
KETCHUP-MASTER-KEY PIC 99.
01 REC-COUNT PIC S9(5) VALUE 0.
PROCEDURE DIVISION.
A000-BEGIN.
OPEN OUTPUT FLAVORS.
MOVE 0 TO KETCHUP-MASTER-KEY.
PERFORM A010-CREATE-RELATIVE-FILE 10 TIMES.
DISPLAY "END OF JOB".
CLOSE FLAVORS.
STOP RUN.
A010-CREATE-RELATIVE-FILE.
ADD 2 TO KETCHUP-MASTER-KEY.
MOVE "Record number" TO KETCHUP-MASTER.
ADD 2 TO REC-COUNT.
MOVE REC-COUNT TO REC-NUM.
WRITE KETCHUP-MASTER
INVALID KEY DISPLAY "BAD WRITE"
STOP RUN.
Statements for Relative File Processing
Processing a relative file involves the following:
1. Opening the file
2. Setting the relative record number
3. Processing the file with valid I/O statements
4. Closing the file
Table 6–5 lists the valid I/O statements and illustrates the following
relationships:
• Organization determines valid access modes.
• Organization and access mode determine valid open modes.
• All three (organization, access, and open mode) enable or disable I/O
statements.
Processing Files and Records 6–31