COBOL Tutorial

COBOL ROLLBACK Statement - Quick Reference

Progress0 of 0 lessons

Overview

The ROLLBACK statement is used to undo database changes and restore the database to its previous state. It cancels all uncommitted changes made since the last COMMIT, ensuring data integrity when errors occur.

Purpose and Usage

Error recovery - Undo changes when errors occur
Data integrity - Maintain database consistency
Transaction management - Control database transactions
Error handling - Provide recovery mechanisms
Concurrent access - Handle multi-user scenarios

Transaction Concept

Transaction Start

├── Update Record 1 ✓

├── Update Record 2 ✓

├── Update Record 3 ✗ (ERROR)

└── ROLLBACK (undo all changes)

Database restored to original state

ROLLBACK undoes all changes when errors occur in a transaction.

Syntax

The ROLLBACK statement has a simple syntax but requires proper transaction setup.

Basic Syntax

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
59
60
61
62
63
64
* Basic ROLLBACK syntax
ROLLBACK
 
* With error handling
IF ERROR-CONDITION
    ROLLBACK
    PERFORM ERROR-HANDLING
END-IF
 
* Complete example
IDENTIFICATION DIVISION.
PROGRAM-ID. ROLLBACK-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
01  ERROR-FLAG        PIC X(1) VALUE "N".
01  FILE-STATUS       PIC XX.
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Start transaction
    PERFORM PROCESS-TRANSACTION
    
    IF ERROR-FLAG = "Y"
        ROLLBACK
        DISPLAY "Transaction rolled back due to errors"
    ELSE
        COMMIT
        DISPLAY "Transaction committed successfully"
    END-IF
    STOP RUN.
 
PROCESS-TRANSACTION.
    * Perform database operations
    PERFORM UPDATE-CUSTOMER
    PERFORM UPDATE-ACCOUNT
    PERFORM UPDATE-TRANSACTION.
 
UPDATE-CUSTOMER.
    * Simulate customer update
    IF CUSTOMER-VALID
        * Update customer record
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.
 
UPDATE-ACCOUNT.
    * Simulate account update
    IF ACCOUNT-VALID
        * Update account record
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.
 
UPDATE-TRANSACTION.
    * Simulate transaction update
    IF TRANSACTION-VALID
        * Update transaction record
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.

ROLLBACK requires transaction support and proper error handling.

ROLLBACK vs COMMIT Comparison

Statement	Action	Use Case
ROLLBACK	Undo changes	Error recovery
COMMIT	Save changes	Successful completion
Both	Transaction control	Data integrity

Practical Examples

These examples demonstrate how to use the ROLLBACK statement effectively in different error recovery scenarios.

Banking Transaction

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
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
IDENTIFICATION DIVISION.
PROGRAM-ID. BANKING-TRANSACTION.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
01  FROM-ACCOUNT      PIC 9(10).
01  TO-ACCOUNT        PIC 9(10).
01  TRANSFER-AMOUNT   PIC 9(8)V99.
01  ERROR-FLAG        PIC X(1) VALUE "N".
01  ERROR-MESSAGE     PIC X(50).
 
PROCEDURE DIVISION.
PROCESS-TRANSFER.
    DISPLAY "Enter from account: "
    ACCEPT FROM-ACCOUNT
    DISPLAY "Enter to account: "
    ACCEPT TO-ACCOUNT
    DISPLAY "Enter amount: "
    ACCEPT TRANSFER-AMOUNT
    
    * Start transaction
    PERFORM VALIDATE-AND-TRANSFER
    
    IF ERROR-FLAG = "Y"
        ROLLBACK
        DISPLAY "Transfer failed: " ERROR-MESSAGE
    ELSE
        COMMIT
        DISPLAY "Transfer completed successfully"
    END-IF
    STOP RUN.
 
VALIDATE-AND-TRANSFER.
    * Validate accounts
    IF FROM-ACCOUNT = TO-ACCOUNT
        MOVE "Y" TO ERROR-FLAG
        MOVE "Cannot transfer to same account" TO ERROR-MESSAGE
        EXIT PARAGRAPH
    END-IF
    
    * Check from account balance
    PERFORM CHECK-BALANCE
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Perform transfer operations
    PERFORM DEBIT-FROM-ACCOUNT
    PERFORM CREDIT-TO-ACCOUNT.
 
CHECK-BALANCE.
    * Simulate balance check
    IF TRANSFER-AMOUNT > 10000
        MOVE "Y" TO ERROR-FLAG
        MOVE "Insufficient funds" TO ERROR-MESSAGE
    END-IF.
 
DEBIT-FROM-ACCOUNT.
    * Simulate debit operation
    IF FROM-ACCOUNT-VALID
        * Debit from account
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Invalid from account" TO ERROR-MESSAGE
    END-IF.
 
CREDIT-TO-ACCOUNT.
    * Simulate credit operation
    IF TO-ACCOUNT-VALID
        * Credit to account
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Invalid to account" TO ERROR-MESSAGE
    END-IF.

ROLLBACK ensures banking transactions maintain data integrity.

Inventory Update

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
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
* Inventory update with ROLLBACK
DATA DIVISION.
WORKING-STORAGE SECTION.
01  PRODUCT-CODE      PIC X(10).
01  QUANTITY          PIC 9(6).
01  ERROR-FLAG        PIC X(1) VALUE "N".
01  UPDATE-STATUS     PIC X(20).
 
PROCEDURE DIVISION.
UPDATE-INVENTORY.
    DISPLAY "Enter product code: "
    ACCEPT PRODUCT-CODE
    DISPLAY "Enter quantity to add: "
    ACCEPT QUANTITY
    
    PERFORM PROCESS-INVENTORY-UPDATE
    
    IF ERROR-FLAG = "Y"
        ROLLBACK
        DISPLAY "Inventory update failed: " UPDATE-STATUS
    ELSE
        COMMIT
        DISPLAY "Inventory updated successfully"
    END-IF.
 
PROCESS-INVENTORY-UPDATE.
    * Validate product
    PERFORM VALIDATE-PRODUCT
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Update inventory records
    PERFORM UPDATE-STOCK-LEVEL
    PERFORM UPDATE-REORDER-POINT
    PERFORM UPDATE-LAST-UPDATE.
 
VALIDATE-PRODUCT.
    * Simulate product validation
    IF PRODUCT-CODE = SPACES
        MOVE "Y" TO ERROR-FLAG
        MOVE "Invalid product code" TO UPDATE-STATUS
    END-IF.
 
UPDATE-STOCK-LEVEL.
    * Simulate stock level update
    IF STOCK-UPDATE-VALID
        * Update stock level
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Stock update failed" TO UPDATE-STATUS
    END-IF.
 
UPDATE-REORDER-POINT.
    * Simulate reorder point update
    IF REORDER-UPDATE-VALID
        * Update reorder point
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Reorder update failed" TO UPDATE-STATUS
    END-IF.
 
UPDATE-LAST-UPDATE.
    * Simulate timestamp update
    IF TIMESTAMP-UPDATE-VALID
        * Update timestamp
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Timestamp update failed" TO UPDATE-STATUS
    END-IF.

ROLLBACK ensures inventory updates maintain consistency.

Customer Order Processing

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
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
* Customer order processing with ROLLBACK
DATA DIVISION.
WORKING-STORAGE SECTION.
01  ORDER-ID          PIC 9(10).
01  CUSTOMER-ID       PIC 9(8).
01  ORDER-AMOUNT      PIC 9(8)V99.
01  ERROR-FLAG        PIC X(1) VALUE "N".
01  PROCESS-STATUS    PIC X(30).
 
PROCEDURE DIVISION.
PROCESS-ORDER.
    DISPLAY "Enter order ID: "
    ACCEPT ORDER-ID
    DISPLAY "Enter customer ID: "
    ACCEPT CUSTOMER-ID
    DISPLAY "Enter order amount: "
    ACCEPT ORDER-AMOUNT
    
    PERFORM PROCESS-ORDER-TRANSACTION
    
    IF ERROR-FLAG = "Y"
        ROLLBACK
        DISPLAY "Order processing failed: " PROCESS-STATUS
    ELSE
        COMMIT
        DISPLAY "Order processed successfully"
    END-IF.
 
PROCESS-ORDER-TRANSACTION.
    * Validate customer
    PERFORM VALIDATE-CUSTOMER
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Process order components
    PERFORM CREATE-ORDER-RECORD
    PERFORM UPDATE-CUSTOMER-BALANCE
    PERFORM UPDATE-INVENTORY
    PERFORM CREATE-INVOICE.
 
VALIDATE-CUSTOMER.
    * Simulate customer validation
    IF CUSTOMER-ID = ZERO
        MOVE "Y" TO ERROR-FLAG
        MOVE "Invalid customer ID" TO PROCESS-STATUS
    END-IF.
 
CREATE-ORDER-RECORD.
    * Simulate order creation
    IF ORDER-CREATION-VALID
        * Create order record
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Order creation failed" TO PROCESS-STATUS
    END-IF.
 
UPDATE-CUSTOMER-BALANCE.
    * Simulate balance update
    IF BALANCE-UPDATE-VALID
        * Update customer balance
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Balance update failed" TO PROCESS-STATUS
    END-IF.
 
UPDATE-INVENTORY.
    * Simulate inventory update
    IF INVENTORY-UPDATE-VALID
        * Update inventory
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Inventory update failed" TO PROCESS-STATUS
    END-IF.
 
CREATE-INVOICE.
    * Simulate invoice creation
    IF INVOICE-CREATION-VALID
        * Create invoice
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
        MOVE "Invoice creation failed" TO PROCESS-STATUS
    END-IF.

ROLLBACK ensures order processing maintains data consistency.

Error Recovery Pattern

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
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
* Generic error recovery pattern with ROLLBACK
PROCEDURE DIVISION.
GENERIC-TRANSACTION.
    * Initialize error handling
    MOVE "N" TO ERROR-FLAG
    
    * Perform transaction operations
    PERFORM TRANSACTION-OPERATIONS
    
    * Check for errors and handle
    IF ERROR-FLAG = "Y"
        PERFORM ERROR-RECOVERY
    ELSE
        PERFORM SUCCESS-HANDLING
    END-IF.
 
TRANSACTION-OPERATIONS.
    * Step 1: Validate input
    PERFORM VALIDATE-INPUT
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Step 2: Process data
    PERFORM PROCESS-DATA
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Step 3: Update database
    PERFORM UPDATE-DATABASE
    IF ERROR-FLAG = "Y"
        EXIT PARAGRAPH
    END-IF
    
    * Step 4: Generate output
    PERFORM GENERATE-OUTPUT.
 
ERROR-RECOVERY.
    * Rollback transaction
    ROLLBACK
    
    * Log error
    PERFORM LOG-ERROR
    
    * Display error message
    DISPLAY "Transaction failed - changes rolled back"
    
    * Perform cleanup
    PERFORM CLEANUP-OPERATIONS.
 
SUCCESS-HANDLING.
    * Commit transaction
    COMMIT
    
    * Log success
    PERFORM LOG-SUCCESS
    
    * Display success message
    DISPLAY "Transaction completed successfully".
 
VALIDATE-INPUT.
    * Simulate input validation
    IF INPUT-VALID
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.
 
PROCESS-DATA.
    * Simulate data processing
    IF PROCESSING-SUCCESSFUL
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.
 
UPDATE-DATABASE.
    * Simulate database update
    IF UPDATE-SUCCESSFUL
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.
 
GENERATE-OUTPUT.
    * Simulate output generation
    IF OUTPUT-SUCCESSFUL
        CONTINUE
    ELSE
        MOVE "Y" TO ERROR-FLAG
    END-IF.

ROLLBACK provides consistent error recovery patterns.

Best Practices and Considerations

Understanding best practices ensures effective use of the ROLLBACK statement.

Best Practices

Check for errors - Always check return codes and file status
Rollback immediately - Call ROLLBACK as soon as errors are detected
Log errors - Record error details before rolling back
Handle cleanup - Perform necessary cleanup operations
Notify users - Provide clear error messages to users
Test thoroughly - Verify ROLLBACK behavior with various scenarios

Transaction Management

Operation	Purpose	When to Use
BEGIN TRANSACTION	Start transaction	Before operations
COMMIT	Save changes	Success completion
ROLLBACK	Undo changes	Error occurrence
SAVEPOINT	Create checkpoint	Complex transactions

Performance Considerations

Transaction size - Keep transactions as small as possible
Rollback cost - Large transactions are expensive to rollback
Resource usage - ROLLBACK may lock resources during recovery
Concurrent access - Consider impact on other users
Database system - Performance varies by database system

ROLLBACK Statement Quick Reference

Usage	Syntax	Example
Basic ROLLBACK	ROLLBACK	ROLLBACK
With error handling	IF error ROLLBACK	IF ERROR-FLAG = "Y" ROLLBACK
Error recovery	ROLLBACK PERFORM ERROR-HANDLING	ROLLBACK PERFORM LOG-ERROR
Transaction pattern	IF success COMMIT ELSE ROLLBACK	IF OK COMMIT ELSE ROLLBACK
Conditional rollback	IF condition ROLLBACK	IF INVALID-DATA ROLLBACK

Test Your Knowledge

1. What is the primary purpose of the ROLLBACK statement in COBOL?

To create a new database
To undo database changes and restore previous state
To commit database changes
To delete database records

2. When should you use ROLLBACK in a COBOL program?

After every successful operation
When an error occurs during database operations
At the beginning of a program
Only when creating new records

3. What happens to database changes after a ROLLBACK?

Changes are saved permanently
Changes are undone and lost
Changes are moved to a backup file
Changes are delayed until later

4. What is the relationship between ROLLBACK and COMMIT?

They are the same thing
ROLLBACK undoes changes, COMMIT saves changes
ROLLBACK is faster than COMMIT
They cannot be used together

5. Can ROLLBACK be used with all types of databases?

Yes, with all databases
Only with relational databases
Only with databases that support transactions
Only with mainframe databases

Frequently Asked Questions

Related Concepts

COMMIT Statement

Using COMMIT to save database changes.

Transaction Management

Understanding transaction management in COBOL.

Error Handling

Error handling techniques in COBOL.

Database Operations

Database and file operations in COBOL.

Data Integrity

Maintaining data integrity in COBOL applications.

RIGHT Clause ROUNDED Clause

COBOL Tutorial

COBOL ROLLBACK Statement - Quick Reference

Overview

Purpose and Usage

Transaction Concept

Syntax

Basic Syntax

ROLLBACK vs COMMIT Comparison

Practical Examples

Banking Transaction

Inventory Update

Customer Order Processing

Error Recovery Pattern

Best Practices and Considerations

Best Practices

Transaction Management

Performance Considerations

ROLLBACK Statement Quick Reference

Test Your Knowledge

Frequently Asked Questions

What is the difference between ROLLBACK and COMMIT in database operations?

How do you implement error handling with ROLLBACK in COBOL?

Can you use ROLLBACK with file operations in COBOL?

What are some common use cases for the ROLLBACK statement?

How does ROLLBACK affect program performance and resource usage?

Related Concepts

COMMIT Statement

Transaction Management

Error Handling

Database Operations

Data Integrity

Related Pages