MainframeMaster

COBOL Data Sorting

Data sorting arranges records in specific order based on key fields using COBOL SORT statement and external utilities. Learn sorting algorithms, multi-key sorting, and techniques for organizing data efficiently.

Basic SORT Statement

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
       WORKING-STORAGE SECTION.
       01 SORT-CONTROL.
           05 SORT-FILE-STATUS PIC X(2).
           05 SORT-RECORD-COUNT PIC 9(6) VALUE 0.
           05 SORT-ERROR-COUNT PIC 9(3) VALUE 0.
       
       PROCEDURE DIVISION.
       PERFORM BASIC-SORT-OPERATION
       
       BASIC-SORT-OPERATION.
           DISPLAY 'Basic SORT Statement demonstration:'
           
           *> Sort customer records by customer ID
           SORT SORT-WORK-FILE
               ON ASCENDING KEY CUSTOMER-ID
               USING CUSTOMER-INPUT-FILE
               GIVING CUSTOMER-OUTPUT-FILE
           
           DISPLAY 'Sort operation completed'
           DISPLAY 'Records sorted by Customer ID in ascending order'
           
           *> Check sort file status
           IF SORT-FILE-STATUS = '00'
               DISPLAY 'Sort completed successfully'
           ELSE
               DISPLAY 'Sort error occurred: ' SORT-FILE-STATUS
               ADD 1 TO SORT-ERROR-COUNT
           END-IF.
       
       *> File definitions would be in FILE SECTION
       *> FD CUSTOMER-INPUT-FILE
       *> FD CUSTOMER-OUTPUT-FILE
       *> SD SORT-WORK-FILE

Use the SORT statement to arrange records in ascending or descending order based on key fields. Specify input file (USING), output file (GIVING), sort keys, and sort order for basic sorting operations.

Multi-Key Sorting

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
       WORKING-STORAGE SECTION.
       01 MULTI-KEY-SORT-CONTROL.
           05 SORT-KEY-COUNT PIC 9(2) VALUE 3.
           05 SORT-KEY-1 PIC X(10) VALUE 'DEPARTMENT'.
           05 SORT-KEY-2 PIC X(10) VALUE 'SALARY'.
           05 SORT-KEY-3 PIC X(10) VALUE 'EMPLOYEE-ID'.
       
       PROCEDURE DIVISION.
       PERFORM MULTI-KEY-SORT-OPERATION
       
       MULTI-KEY-SORT-OPERATION.
           DISPLAY 'Multi-Key SORT demonstration:'
           
           *> Sort by multiple keys: Department (ASC), Salary (DESC), Employee ID (ASC)
           SORT SORT-WORK-FILE
               ON ASCENDING KEY EMPLOYEE-DEPARTMENT
               ON DESCENDING KEY EMPLOYEE-SALARY
               ON ASCENDING KEY EMPLOYEE-ID
               USING EMPLOYEE-INPUT-FILE
               GIVING EMPLOYEE-OUTPUT-FILE
           
           DISPLAY 'Multi-key sort completed:'
           DISPLAY 'Primary Key: Department (Ascending)'
           DISPLAY 'Secondary Key: Salary (Descending)'
           DISPLAY 'Tertiary Key: Employee ID (Ascending)'
           
           *> Verify sort results
           PERFORM VERIFY-SORT-RESULTS.
       
       VERIFY-SORT-RESULTS.
           OPEN INPUT EMPLOYEE-OUTPUT-FILE
           MOVE 0 TO SORT-RECORD-COUNT
           
           PERFORM UNTIL EOF
               READ EMPLOYEE-OUTPUT-FILE AT END SET EOF TO TRUE
               NOT AT END
                   ADD 1 TO SORT-RECORD-COUNT
                   DISPLAY 'Sorted Record ' SORT-RECORD-COUNT ':'
                   DISPLAY '  Department: ' EMPLOYEE-DEPARTMENT
                   DISPLAY '  Salary: ' EMPLOYEE-SALARY
                   DISPLAY '  Employee ID: ' EMPLOYEE-ID
               END-READ
           END-PERFORM
           
           CLOSE EMPLOYEE-OUTPUT-FILE.

Implement multi-key sorting by specifying multiple sort keys with different sort orders. Use primary, secondary, and tertiary keys to create complex sort criteria for sophisticated data organization.

Sort with Input/Output Procedures

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
       WORKING-STORAGE SECTION.
       01 PROCEDURE-SORT-CONTROL.
           05 INPUT-PROCEDURE-COUNT PIC 9(4) VALUE 0.
           05 OUTPUT-PROCEDURE-COUNT PIC 9(4) VALUE 0.
           05 TOTAL-RECORDS-PROCESSED PIC 9(6) VALUE 0.
       
       PROCEDURE DIVISION.
       PERFORM PROCEDURE-SORT-OPERATION
       
       PROCEDURE-SORT-OPERATION.
           DISPLAY 'SORT with Input/Output Procedures demonstration:'
           
           *> Sort with input and output procedures
           SORT SORT-WORK-FILE
               ON ASCENDING KEY CUSTOMER-ID
               INPUT PROCEDURE IS INPUT-PROCEDURE
               OUTPUT PROCEDURE IS OUTPUT-PROCEDURE
           
           DISPLAY 'Procedure-based sort completed'
           DISPLAY 'Input records processed: ' INPUT-PROCEDURE-COUNT
           DISPLAY 'Output records processed: ' OUTPUT-PROCEDURE-COUNT
           DISPLAY 'Total records: ' TOTAL-RECORDS-PROCESSED.
       
       INPUT-PROCEDURE SECTION.
       INPUT-PROCEDURE.
           DISPLAY 'Input Procedure: Processing input records'
           
           OPEN INPUT CUSTOMER-INPUT-FILE
           
           PERFORM UNTIL EOF
               READ CUSTOMER-INPUT-FILE AT END SET EOF TO TRUE
               NOT AT END
                   *> Apply input filtering or transformation
                   IF CUSTOMER-STATUS = 'A'
                       RELEASE SORT-RECORD FROM CUSTOMER-RECORD
                       ADD 1 TO INPUT-PROCEDURE-COUNT
                   END-IF
               END-READ
           END-PERFORM
           
           CLOSE CUSTOMER-INPUT-FILE.
       
       OUTPUT-PROCEDURE SECTION.
       OUTPUT-PROCEDURE.
           DISPLAY 'Output Procedure: Processing sorted records'
           
           OPEN OUTPUT CUSTOMER-OUTPUT-FILE
           
           PERFORM UNTIL EOF
               RETURN SORT-WORK-FILE AT END SET EOF TO TRUE
               NOT AT END
                   *> Apply output formatting or additional processing
                   WRITE CUSTOMER-OUTPUT-RECORD FROM SORT-RECORD
                   ADD 1 TO OUTPUT-PROCEDURE-COUNT
               END-RETURN
           END-PERFORM
           
           CLOSE CUSTOMER-OUTPUT-FILE.

Use input and output procedures with SORT statement for custom processing. Input procedures filter or transform data before sorting, while output procedures format or process data after sorting.

External Sort Utility

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
       WORKING-STORAGE SECTION.
       01 EXTERNAL-SORT-CONTROL.
           05 SORT-UTILITY-NAME PIC X(8) VALUE 'SORT'.
           05 SORT-PARAMETERS PIC X(100).
           05 SORT-RETURN-CODE PIC 9(4).
           05 SORT-MESSAGE PIC X(50).
       
       PROCEDURE DIVISION.
       PERFORM EXTERNAL-SORT-OPERATION
       
       EXTERNAL-SORT-OPERATION.
           DISPLAY 'External Sort Utility demonstration:'
           
           *> Prepare sort parameters
           STRING 'FIELDS=(1,6,CH,A,7,30,CH,A,37,10,PD,A)'
                  ',FORMAT=CH'
                  ',EQUALS'
           INTO SORT-PARAMETERS
           
           DISPLAY 'Sort Parameters: ' SORT-PARAMETERS
           
           *> Call external sort utility
           CALL SORT-UTILITY-NAME USING SORT-PARAMETERS
           
           *> Check return code
           IF SORT-RETURN-CODE = 0
               DISPLAY 'External sort completed successfully'
               MOVE 'SORT COMPLETED' TO SORT-MESSAGE
           ELSE
               DISPLAY 'External sort failed with return code: ' SORT-RETURN-CODE
               MOVE 'SORT FAILED' TO SORT-MESSAGE
           END-IF
           
           DISPLAY 'Sort Message: ' SORT-MESSAGE.

Use external sort utilities for large datasets that exceed memory capacity. Define sort parameters including field specifications, data formats, and sort options for efficient external sorting.

Sort Performance Optimization

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
       WORKING-STORAGE SECTION.
       01 SORT-PERFORMANCE-CONTROL.
           05 SORT-MEMORY-SIZE PIC 9(8) VALUE 1000000.
           05 SORT-BUFFER-SIZE PIC 9(6) VALUE 10000.
           05 SORT-TAPE-COUNT PIC 9(2) VALUE 4.
           05 SORT-PERFORMANCE-METRICS.
               10 SORT-START-TIME PIC 9(14).
               10 SORT-END-TIME PIC 9(14).
               10 SORT-DURATION PIC 9(6).
               10 RECORDS-PER-SECOND PIC 9(6).
       
       PROCEDURE DIVISION.
       PERFORM OPTIMIZED-SORT-OPERATION
       
       OPTIMIZED-SORT-OPERATION.
           DISPLAY 'Optimized SORT Operation demonstration:'
           
           MOVE FUNCTION CURRENT-TIME TO SORT-START-TIME
           
           *> Optimized sort with performance parameters
           SORT SORT-WORK-FILE
               ON ASCENDING KEY CUSTOMER-ID
               USING CUSTOMER-INPUT-FILE
               GIVING CUSTOMER-OUTPUT-FILE
           
           MOVE FUNCTION CURRENT-TIME TO SORT-END-TIME
           COMPUTE SORT-DURATION = SORT-END-TIME - SORT-START-TIME
           
           DISPLAY 'Sort Performance Metrics:'
           DISPLAY 'Memory Size: ' SORT-MEMORY-SIZE ' bytes'
           DISPLAY 'Buffer Size: ' SORT-BUFFER-SIZE ' records'
           DISPLAY 'Tape Count: ' SORT-TAPE-COUNT
           DISPLAY 'Sort Duration: ' SORT-DURATION ' milliseconds'
           
           IF SORT-DURATION > 0
               COMPUTE RECORDS-PER-SECOND = (SORT-RECORD-COUNT * 1000) / SORT-DURATION
               DISPLAY 'Records per Second: ' RECORDS-PER-SECOND
           END-IF.

Optimize sort performance by configuring memory size, buffer size, tape count, and other parameters. Monitor sort duration and throughput to achieve optimal sorting performance for large datasets.

Sort Error Handling

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
       WORKING-STORAGE SECTION.
       01 SORT-ERROR-HANDLING.
           05 SORT-ERROR-TYPES.
               10 INPUT-ERROR PIC 9(3) VALUE 0.
               10 OUTPUT-ERROR PIC 9(3) VALUE 0.
               10 SORT-ERROR PIC 9(3) VALUE 0.
               10 MEMORY-ERROR PIC 9(3) VALUE 0.
           05 ERROR-RESPONSES.
               10 ERROR-RECOVERY-ACTION PIC X(20).
               10 ERROR-NOTIFICATION PIC X(50).
               10 ERROR-LOG-ENTRY PIC X(100).
       
       PROCEDURE DIVISION.
       PERFORM SORT-WITH-ERROR-HANDLING
       
       SORT-WITH-ERROR-HANDLING.
           DISPLAY 'SORT Error Handling demonstration:'
           
           *> Attempt sort operation with error handling
           SORT SORT-WORK-FILE
               ON ASCENDING KEY CUSTOMER-ID
               USING CUSTOMER-INPUT-FILE
               GIVING CUSTOMER-OUTPUT-FILE
           
           *> Check for various error conditions
           EVALUATE SORT-FILE-STATUS
               WHEN '00'
                   DISPLAY 'Sort completed successfully'
               WHEN '02'
                   DISPLAY 'Sort completed with warnings'
                   ADD 1 TO SORT-ERROR
               WHEN '04'
                   DISPLAY 'Sort completed with data truncation'
                   ADD 1 TO OUTPUT-ERROR
               WHEN '10'
                   DISPLAY 'End of file reached'
               WHEN '22'
                   DISPLAY 'Duplicate key error'
                   ADD 1 TO SORT-ERROR
               WHEN '23'
                   DISPLAY 'Record not found'
                   ADD 1 TO INPUT-ERROR
               WHEN '24'
                   DISPLAY 'Boundary violation'
                   ADD 1 TO MEMORY-ERROR
               WHEN OTHER
                   DISPLAY 'Unexpected error: ' SORT-FILE-STATUS
                   ADD 1 TO SORT-ERROR
           END-EVALUATE
           
           DISPLAY 'Error Handling Results:'
           DISPLAY 'Input Errors: ' INPUT-ERROR
           DISPLAY 'Output Errors: ' OUTPUT-ERROR
           DISPLAY 'Sort Errors: ' SORT-ERROR
           DISPLAY 'Memory Errors: ' MEMORY-ERROR.

Implement comprehensive error handling for sort operations including input errors, output errors, sort errors, and memory errors. Use EVALUATE statement to handle different error conditions and provide appropriate responses.

Sort Data Validation

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
       WORKING-STORAGE SECTION.
       01 SORT-VALIDATION-CONTROL.
           05 VALIDATION-RESULTS.
               10 VALID-RECORDS PIC 9(6) VALUE 0.
               10 INVALID-RECORDS PIC 9(6) VALUE 0.
               10 DUPLICATE-RECORDS PIC 9(6) VALUE 0.
               10 TOTAL-RECORDS PIC 9(6) VALUE 0.
           05 VALIDATION-CHECKS.
               10 KEY-VALIDATION PIC X VALUE 'Y'.
               10 FORMAT-VALIDATION PIC X VALUE 'Y'.
               10 RANGE-VALIDATION PIC X VALUE 'Y'.
       
       PROCEDURE DIVISION.
       PERFORM SORT-VALIDATION-OPERATION
       
       SORT-VALIDATION-OPERATION.
           DISPLAY 'SORT Data Validation demonstration:'
           
           *> Validate data before sorting
           PERFORM VALIDATE-INPUT-DATA
           
           IF VALIDATION-SUCCESSFUL
               DISPLAY 'Data validation passed - proceeding with sort'
               
               SORT SORT-WORK-FILE
                   ON ASCENDING KEY CUSTOMER-ID
                   USING CUSTOMER-INPUT-FILE
                   GIVING CUSTOMER-OUTPUT-FILE
               
               DISPLAY 'Sort completed with validated data'
           ELSE
               DISPLAY 'Data validation failed - sort aborted'
               DISPLAY 'Invalid records found: ' INVALID-RECORDS
           END-IF
           
           DISPLAY 'Validation Results:'
           DISPLAY 'Valid Records: ' VALID-RECORDS
           DISPLAY 'Invalid Records: ' INVALID-RECORDS
           DISPLAY 'Duplicate Records: ' DUPLICATE-RECORDS
           DISPLAY 'Total Records: ' TOTAL-RECORDS.
       
       VALIDATE-INPUT-DATA.
           OPEN INPUT CUSTOMER-INPUT-FILE
           MOVE 0 TO VALID-RECORDS
           MOVE 0 TO INVALID-RECORDS
           
           PERFORM UNTIL EOF
               READ CUSTOMER-INPUT-FILE AT END SET EOF TO TRUE
               NOT AT END
                   ADD 1 TO TOTAL-RECORDS
                   PERFORM VALIDATE-SINGLE-RECORD
               END-READ
           END-PERFORM
           
           CLOSE CUSTOMER-INPUT-FILE.

Validate data before sorting to ensure data quality and prevent sort errors. Check key fields, data formats, ranges, and duplicates to ensure reliable sort operations.

Sort Best Practices

cobol
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
       WORKING-STORAGE SECTION.
       01 SORT-BEST-PRACTICES.
           05 SORT-DESIGN-PRINCIPLES.
               10 SORT-KEY-SELECTION PIC X(20) VALUE 'MEANINGFUL'.
               10 SORT-ORDER-CONSISTENCY PIC X(20) VALUE 'CONSISTENT'.
               10 SORT-PERFORMANCE PIC X(20) VALUE 'OPTIMIZED'.
           05 SORT-MAINTENANCE.
               10 SORT-DOCUMENTATION PIC X(50) VALUE 'WELL DOCUMENTED'.
               10 SORT-TESTING PIC X(50) VALUE 'THOROUGHLY TESTED'.
               10 SORT-MONITORING PIC X(50) VALUE 'CONTINUOUSLY MONITORED'.
       
       PROCEDURE DIVISION.
       PERFORM DEMONSTRATE-SORT-BEST-PRACTICES
       
       DEMONSTRATE-SORT-BEST-PRACTICES.
           DISPLAY 'SORT Best Practices demonstration:'
           DISPLAY 'Key Selection: ' SORT-KEY-SELECTION
           DISPLAY 'Order Consistency: ' SORT-ORDER-CONSISTENCY
           DISPLAY 'Performance: ' SORT-PERFORMANCE
           DISPLAY 'Documentation: ' SORT-DOCUMENTATION
           DISPLAY 'Testing: ' SORT-TESTING
           DISPLAY 'Monitoring: ' SORT-MONITORING
           
           DISPLAY 'Best Practices Guidelines:'
           DISPLAY '1. Choose meaningful sort keys'
           DISPLAY '2. Maintain consistent sort order'
           DISPLAY '3. Optimize sort performance'
           DISPLAY '4. Document sort logic clearly'
           DISPLAY '5. Test sort operations thoroughly'
           DISPLAY '6. Monitor sort performance continuously'.

Follow best practices for sort operations: choose meaningful sort keys, maintain consistent sort order, optimize performance, document sort logic, test thoroughly, and monitor performance continuously.

Data Sharing

Shared data areas and communication

Sorting Operations

Sorting operations and techniques