EMPTY-CHECK in COBOL

Learn about EMPTY-CHECK in COBOL, including its usage in data validation, field verification, and handling of empty or null values.

Understanding EMPTY-CHECK

EMPTY-CHECK is a crucial feature in COBOL for validating data fields and ensuring they contain meaningful values. It helps maintain data integrity by identifying empty or null fields before they cause processing errors.

Key Characteristics

Validates field contents
Identifies truly empty fields
Works with various data types
Supports data quality control

Basic EMPTY-CHECK Usage

Simple Field Validation

cobol

1
2
3
4
5
6
7
8
9
10
11
       WORKING-STORAGE SECTION.
       01  WS-CUSTOMER-RECORD.
           05  WS-CUSTOMER-NAME   PIC X(30).
           05  WS-CUSTOMER-ID     PIC X(10).
       01  WS-VALID-FLAG         PIC X VALUE 'Y'.
       
       PROCEDURE DIVISION.
           IF WS-CUSTOMER-NAME = SPACES
               MOVE 'N' TO WS-VALID-FLAG
               DISPLAY "Error: Customer name is empty"
           END-IF

Comprehensive Empty Check

cobol

1
2
3
4
5
6
       IF WS-CUSTOMER-NAME = SPACES OR
          WS-CUSTOMER-NAME = LOW-VALUES
           MOVE 'N' TO WS-VALID-FLAG
           DISPLAY "Error: Invalid customer name"
           PERFORM HANDLE-EMPTY-FIELD
       END-IF

Advanced Validation Techniques

Multiple Field 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
       WORKING-STORAGE SECTION.
       01  WS-ERROR-COUNT        PIC 9(2) VALUE ZERO.
       01  WS-ERROR-MESSAGE      PIC X(50).
       
       PROCEDURE DIVISION.
           PERFORM CHECK-REQUIRED-FIELDS
           IF WS-ERROR-COUNT > 0
               PERFORM DISPLAY-ERROR-SUMMARY
           ELSE
               PERFORM PROCESS-RECORD
           END-IF.
 
       CHECK-REQUIRED-FIELDS.
           IF WS-CUSTOMER-NAME = SPACES
               ADD 1 TO WS-ERROR-COUNT
               STRING "Customer name required"
                   DELIMITED BY SIZE
                   INTO WS-ERROR-MESSAGE
               PERFORM DISPLAY-ERROR
           END-IF
           
           IF WS-CUSTOMER-ID = SPACES
               ADD 1 TO WS-ERROR-COUNT
               STRING "Customer ID required"
                   DELIMITED BY SIZE
                   INTO WS-ERROR-MESSAGE
               PERFORM DISPLAY-ERROR
           END-IF

Numeric Field Validation

Special handling for numeric fields that might be empty:

cobol

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
       WORKING-STORAGE SECTION.
       01  WS-AMOUNT            PIC 9(7)V99.
       01  WS-AMOUNT-X REDEFINES WS-AMOUNT PIC X(9).
       
       PROCEDURE DIVISION.
           IF WS-AMOUNT-X = SPACES
               MOVE ZEROS TO WS-AMOUNT
               PERFORM HANDLE-EMPTY-AMOUNT
           ELSE
               IF WS-AMOUNT = ZEROS
                   PERFORM HANDLE-ZERO-AMOUNT
               ELSE
                   PERFORM PROCESS-AMOUNT
               END-IF
           END-IF

Handling Multiple Empty Conditions

Comprehensive Empty Check

cobol

1
2
3
4
5
6
7
8
9
10
11
12
       EVALUATE TRUE
           WHEN WS-FIELD = SPACES
               PERFORM HANDLE-SPACES
           WHEN WS-FIELD = LOW-VALUES
               PERFORM HANDLE-LOW-VALUES
           WHEN WS-FIELD = HIGH-VALUES
               PERFORM HANDLE-HIGH-VALUES
           WHEN WS-FIELD = ZEROS
               PERFORM HANDLE-ZEROS
           WHEN OTHER
               PERFORM PROCESS-VALID-FIELD
       END-EVALUATE

Best Practices

Check for multiple empty conditions
Validate before processing
Maintain error logs
Use appropriate data types
Consider field requirements

Error Handling Patterns

Structured 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
       WORKING-STORAGE SECTION.
       01  WS-ERROR-TABLE.
           05  WS-ERROR-ENTRY OCCURS 10 TIMES.
               10  WS-ERROR-FIELD    PIC X(20).
               10  WS-ERROR-DESC     PIC X(50).
       01  WS-ERROR-IDX          PIC 99 VALUE 1.
       
       PROCEDURE DIVISION.
           PERFORM VALIDATE-FIELDS
           IF WS-ERROR-IDX > 1
               PERFORM DISPLAY-ERRORS
               PERFORM HANDLE-VALIDATION-FAILURE
           ELSE
               PERFORM PROCESS-VALID-RECORD
           END-IF.
 
       VALIDATE-FIELDS.
           IF WS-CUSTOMER-NAME = SPACES
               MOVE "CUSTOMER-NAME" TO WS-ERROR-FIELD(WS-ERROR-IDX)
               MOVE "Required field is empty" 
                   TO WS-ERROR-DESC(WS-ERROR-IDX)
               ADD 1 TO WS-ERROR-IDX
           END-IF

Performance Considerations

Optimize validation order
Batch similar checks
Use efficient comparisons
Consider field sizes
Minimize redundant checks

EMPTY-CHECK in COBOL

Understanding EMPTY-CHECK

Key Characteristics

Basic EMPTY-CHECK Usage

Simple Field Validation

Comprehensive Empty Check

Advanced Validation Techniques

Multiple Field Validation

Numeric Field Validation

Handling Multiple Empty Conditions

Comprehensive Empty Check

Best Practices

Error Handling Patterns

Structured Error Handling

Performance Considerations

Frequently Asked Questions

Related Pages

Related Concepts

Data Validation

Field Processing

Error Handling