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COBOL Tutorial

COBOL RAISE - Quick Reference

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Overview

The RAISE statement in COBOL is used to explicitly raise or throw an exception. It allows programs to signal error conditions or exceptional situations that need to be handled by exception handlers, providing a structured approach to error management.

Purpose and Usage

  • Exception signaling for error conditions
  • Structured error handling
  • Error propagation up the call stack
  • Business rule validation
  • Robust error management

Syntax

The RAISE statement follows specific syntax patterns:

Basic Syntax

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* Basic RAISE statement
RAISE exception-name.
 
* RAISE with parameters
RAISE exception-name USING parameter1, parameter2.
 
* RAISE with condition
IF error-condition
    RAISE validation-error
END-IF.
 
* RAISE in exception handler
ON EXCEPTION
    RAISE propagated-error
END-EXCEPTION.

RAISE can be used with or without parameters.

Exception Definition

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* Defining custom exceptions
01  validation-error EXCEPTION.
01  business-rule-error EXCEPTION.
01  system-error EXCEPTION.
 
* Using predefined exceptions
RAISE INVALID-KEY.
RAISE FILE-NOT-FOUND.
RAISE DATA-EXCEPTION.

Practical Examples

Here are some practical uses of the RAISE statement in COBOL:

Data Validation

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* Data validation with RAISE
PROCEDURE DIVISION.
VALIDATE-CUSTOMER-DATA.
    * Validate customer age
    IF customer-age < 18
        RAISE invalid-age-error
    END-IF.
    
    * Validate customer balance
    IF customer-balance < 0
        RAISE negative-balance-error
    END-IF.
    
    * Validate customer name
    IF customer-name = SPACES
        RAISE missing-name-error
    END-IF.
    
    DISPLAY "Customer data validation successful"
    EXIT PARAGRAPH.
 
* Exception handler for validation errors
HANDLE-VALIDATION-ERRORS.
    ON EXCEPTION invalid-age-error
        DISPLAY "Error: Customer must be 18 or older"
        PERFORM age-error-handling
    ON EXCEPTION negative-balance-error
        DISPLAY "Error: Customer balance cannot be negative"
        PERFORM balance-error-handling
    ON EXCEPTION missing-name-error
        DISPLAY "Error: Customer name is required"
        PERFORM name-error-handling
END-EXCEPTION.

Using RAISE for data validation error handling.

Business Rule Enforcement

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* Business rule enforcement with RAISE
PROCEDURE DIVISION.
PROCESS-TRANSACTION.
    * Check transaction limits
    IF transaction-amount > max-transaction-limit
        RAISE transaction-limit-exceeded
    END-IF.
    
    * Check account status
    IF account-status = "FROZEN"
        RAISE account-frozen-error
    END-IF.
    
    * Check available balance
    IF transaction-amount > available-balance
        RAISE insufficient-funds-error
    END-IF.
    
    * Process transaction if all checks pass
    PERFORM execute-transaction
    EXIT PARAGRAPH.
 
* Exception handling for business rules
HANDLE-BUSINESS-ERRORS.
    ON EXCEPTION transaction-limit-exceeded
        DISPLAY "Error: Transaction amount exceeds limit"
        PERFORM limit-error-handling
    ON EXCEPTION account-frozen-error
        DISPLAY "Error: Account is frozen"
        PERFORM frozen-account-handling
    ON EXCEPTION insufficient-funds-error
        DISPLAY "Error: Insufficient funds"
        PERFORM insufficient-funds-handling
END-EXCEPTION.

Using RAISE for business rule enforcement.

Best Practices

  • Use RAISE for exceptional conditions, not normal program flow.
  • Define meaningful exception names that describe the error condition.
  • Provide appropriate exception handlers for all raised exceptions.
  • Use RAISE to propagate errors up the call stack when appropriate.
  • Document the conditions that cause each exception to be raised.
  • Consider the performance implications of exception handling.

Common Pitfalls

  • Raising exceptions for normal program flow instead of exceptional conditions.
  • Not providing exception handlers for raised exceptions.
  • Using generic exception names that don\'t describe the specific error.
  • Raising exceptions without proper error context or information.
  • Not considering the impact of exceptions on program performance.

Test Your Knowledge

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

  • To terminate the program
  • To raise or throw an exception
  • To increase a counter
  • To display a message

2. When should you use the RAISE statement?

  • Always
  • When you want to signal an error condition
  • Only in debugging
  • Only in test programs

3. What happens when a RAISE statement is executed?

  • The program terminates
  • Control transfers to an exception handler
  • A message is displayed
  • Nothing happens

4. What is the relationship between RAISE and exception handling?

  • They are unrelated
  • RAISE creates exceptions, exception handlers catch them
  • RAISE is obsolete
  • They are the same thing

5. Is RAISE supported in all COBOL implementations?

  • Yes, always
  • No, it depends on the COBOL implementation
  • Only in modern COBOL
  • Only in object-oriented COBOL

Frequently Asked Questions

Related Concepts

Exception Handling

Comprehensive exception handling in COBOL.

ON EXCEPTION

Handling exceptions in COBOL.

Error Handling

Error handling strategies and best practices.

Data Validation

Validating data with exception handling.

Business Rules

Implementing business rules with exceptions.

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