What is business logic in COBOL?

Business logic in COBOL refers to the core application logic that implements business rules, decision-making processes, workflow control, and data processing rules that define how the application behaves.

How do you implement business rules in COBOL?

Business rules are implemented using conditional statements (IF-THEN-ELSE), decision tables, validation routines, calculation logic, and workflow control structures that enforce business requirements.

What are the key components of COBOL business logic?

Key components include validation logic, calculation routines, decision-making processes, workflow control, business rule enforcement, data transformation logic, and error handling procedures.

How do you structure business logic in COBOL programs?

Business logic is structured using modular paragraphs, decision tables, validation routines, calculation sections, and workflow control structures organized in the Procedure Division.

What is decision table implementation in COBOL?

Decision tables in COBOL implement complex business rules using structured conditional logic, lookup tables, and rule-based processing to handle multiple business scenarios efficiently.

How do you validate business rules in COBOL?

Business rule validation is implemented using validation routines, error checking, data integrity checks, and business constraint enforcement throughout the application logic.

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COBOL Business Logic

Business logic in COBOL represents the core application logic that implements business rules, decision-making processes, and workflow control. It defines how the application processes data, makes decisions, and enforces business requirements throughout the program execution.

Understanding Business Logic

Business logic encompasses all the rules, calculations, validations, and decision-making processes that define how a COBOL application behaves. It separates business requirements from technical implementation details, making applications maintainable and adaptable to changing business needs.

Core Components of Business Logic

1. Business Rule Implementation

Business rules define the constraints, calculations, and decision criteria that govern how the application processes data and makes decisions.

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. BUSINESS-RULES.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 CUSTOMER-DATA.
           05 CUSTOMER-ID        PIC 9(6).
           05 CUSTOMER-NAME      PIC X(30).
           05 ACCOUNT-BALANCE    PIC 9(8)V99.
           05 CREDIT-LIMIT       PIC 9(8)V99.
           05 CUSTOMER-TYPE      PIC X(1).
               88 PREMIUM-CUSTOMER VALUE 'P'.
               88 STANDARD-CUSTOMER VALUE 'S'.
               88 BASIC-CUSTOMER VALUE 'B'.
       
       01 BUSINESS-RULES.
           05 MINIMUM-BALANCE    PIC 9(8)V99 VALUE 1000.
           05 OVERDRAFT-FEE      PIC 9(4)V99 VALUE 25.00.
           05 INTEREST-RATE      PIC 9(3)V9999 VALUE 0.0525.
           05 SERVICE-FEE        PIC 9(4)V99 VALUE 5.00.
       
       01 CALCULATION-RESULTS.
           05 NEW-BALANCE        PIC 9(8)V99.
           05 INTEREST-AMOUNT    PIC 9(8)V99.
           05 SERVICE-CHARGE    PIC 9(8)V99.
           05 TOTAL-FEES        PIC 9(8)V99.
       
       PROCEDURE DIVISION.
       MAIN-BUSINESS-LOGIC.
           PERFORM INITIALIZE-BUSINESS-RULES
           PERFORM PROCESS-CUSTOMER-TRANSACTION
           PERFORM APPLY-BUSINESS-RULES
           PERFORM CALCULATE-FEES-AND-INTEREST
           PERFORM UPDATE-CUSTOMER-BALANCE
           STOP RUN.
       
       APPLY-BUSINESS-RULES.
           EVALUATE CUSTOMER-TYPE
               WHEN 'P'
                   PERFORM PREMIUM-CUSTOMER-RULES
               WHEN 'S'
                   PERFORM STANDARD-CUSTOMER-RULES
               WHEN 'B'
                   PERFORM BASIC-CUSTOMER-RULES
               WHEN OTHER
                   PERFORM DEFAULT-CUSTOMER-RULES
           END-EVALUATE.
       
       PREMIUM-CUSTOMER-RULES.
           MOVE 0.035 TO INTEREST-RATE
           MOVE 0 TO SERVICE-FEE
           MOVE 5000 TO MINIMUM-BALANCE.
       
       STANDARD-CUSTOMER-RULES.
           MOVE 0.045 TO INTEREST-RATE
           MOVE 2.50 TO SERVICE-FEE
           MOVE 2000 TO MINIMUM-BALANCE.
       
       BASIC-CUSTOMER-RULES.
           MOVE 0.0525 TO INTEREST-RATE
           MOVE 5.00 TO SERVICE-FEE
           MOVE 1000 TO MINIMUM-BALANCE.

2. Decision-Making Logic

Decision-making logic implements complex business decisions using conditional statements, decision tables, and rule-based processing.

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       WORKING-STORAGE SECTION.
       01 TRANSACTION-DATA.
           05 TRANSACTION-TYPE   PIC X(1).
               88 DEPOSIT VALUE 'D'.
               88 WITHDRAWAL VALUE 'W'.
               88 TRANSFER VALUE 'T'.
               88 PAYMENT VALUE 'P'.
           05 TRANSACTION-AMOUNT PIC 9(8)V99.
           05 TRANSACTION-DATE   PIC X(10).
           05 ACCOUNT-TYPE       PIC X(1).
               88 CHECKING VALUE 'C'.
               88 SAVINGS VALUE 'S'.
               88 BUSINESS VALUE 'B'.
       
       01 DECISION-CRITERIA.
           05 DAILY-LIMIT        PIC 9(8)V99.
           05 MONTHLY-LIMIT      PIC 9(8)V99.
           05 TRANSACTION-FEE   PIC 9(4)V99.
           05 APPROVAL-REQUIRED PIC X(1).
               88 APPROVAL-NEEDED VALUE 'Y'.
               88 NO-APPROVAL VALUE 'N'.
       
       PROCEDURE DIVISION.
       DECISION-MAKING-LOGIC.
           PERFORM EVALUATE-TRANSACTION-TYPE
           PERFORM CHECK-TRANSACTION-LIMITS
           PERFORM DETERMINE-APPROVAL-REQUIREMENT
           PERFORM APPLY-TRANSACTION-FEES
           PERFORM FINALIZE-TRANSACTION-DECISION.
       
       EVALUATE-TRANSACTION-TYPE.
           EVALUATE TRANSACTION-TYPE
               WHEN 'D'
                   PERFORM PROCESS-DEPOSIT-LOGIC
               WHEN 'W'
                   PERFORM PROCESS-WITHDRAWAL-LOGIC
               WHEN 'T'
                   PERFORM PROCESS-TRANSFER-LOGIC
               WHEN 'P'
                   PERFORM PROCESS-PAYMENT-LOGIC
               WHEN OTHER
                   PERFORM INVALID-TRANSACTION-LOGIC
           END-EVALUATE.
       
       PROCESS-WITHDRAWAL-LOGIC.
           EVALUATE ACCOUNT-TYPE
               WHEN 'C'
                   MOVE 1000 TO DAILY-LIMIT
                   MOVE 10000 TO MONTHLY-LIMIT
                   MOVE 2.50 TO TRANSACTION-FEE
               WHEN 'S'
                   MOVE 500 TO DAILY-LIMIT
                   MOVE 5000 TO MONTHLY-LIMIT
                   MOVE 1.50 TO TRANSACTION-FEE
               WHEN 'B'
                   MOVE 5000 TO DAILY-LIMIT
                   MOVE 50000 TO MONTHLY-LIMIT
                   MOVE 5.00 TO TRANSACTION-FEE
           END-EVALUATE.
       
       CHECK-TRANSACTION-LIMITS.
           IF TRANSACTION-AMOUNT > DAILY-LIMIT
               MOVE 'Y' TO APPROVAL-REQUIRED
               PERFORM LOG-HIGH-VALUE-TRANSACTION
           ELSE
               MOVE 'N' TO APPROVAL-REQUIRED
           END-IF.

3. Workflow Control Logic

Workflow control logic manages the sequence of business processes, ensuring proper execution order and handling of business scenarios.

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       WORKING-STORAGE SECTION.
       01 WORKFLOW-CONTROL.
           05 CURRENT-STEP       PIC 9(2).
           05 TOTAL-STEPS        PIC 9(2) VALUE 8.
           05 WORKFLOW-STATUS    PIC X(1).
               88 WORKFLOW-ACTIVE VALUE 'A'.
               88 WORKFLOW-PAUSED VALUE 'P'.
               88 WORKFLOW-COMPLETE VALUE 'C'.
               88 WORKFLOW-ERROR VALUE 'E'.
           05 STEP-RESULT        PIC X(1).
               88 STEP-SUCCESS VALUE 'S'.
               88 STEP-FAILURE VALUE 'F'.
               88 STEP-SKIP VALUE 'K'.
       
       01 BUSINESS-WORKFLOW.
           05 STEP-1-NAME        PIC X(20) VALUE 'VALIDATE-INPUT'.
           05 STEP-2-NAME        PIC X(20) VALUE 'CHECK-BALANCE'.
           05 STEP-3-NAME        PIC X(20) VALUE 'VERIFY-LIMITS'.
           05 STEP-4-NAME        PIC X(20) VALUE 'PROCESS-TRANSACTION'.
           05 STEP-5-NAME        PIC X(20) VALUE 'UPDATE-RECORDS'.
           05 STEP-6-NAME        PIC X(20) VALUE 'CALCULATE-FEES'.
           05 STEP-7-NAME        PIC X(20) VALUE 'GENERATE-RECEIPT'.
           05 STEP-8-NAME        PIC X(20) VALUE 'LOG-TRANSACTION'.
       
       PROCEDURE DIVISION.
       BUSINESS-WORKFLOW-CONTROL.
           MOVE 1 TO CURRENT-STEP
           MOVE 'A' TO WORKFLOW-STATUS
           
           PERFORM UNTIL WORKFLOW-STATUS = 'C' OR 'E'
               PERFORM EXECUTE-CURRENT-STEP
               PERFORM EVALUATE-STEP-RESULT
               PERFORM DETERMINE-NEXT-STEP
           END-PERFORM.
       
       EXECUTE-CURRENT-STEP.
           EVALUATE CURRENT-STEP
               WHEN 1
                   PERFORM VALIDATE-INPUT-DATA
               WHEN 2
                   PERFORM CHECK-ACCOUNT-BALANCE
               WHEN 3
                   PERFORM VERIFY-TRANSACTION-LIMITS
               WHEN 4
                   PERFORM PROCESS-TRANSACTION-LOGIC
               WHEN 5
                   PERFORM UPDATE-ACCOUNT-RECORDS
               WHEN 6
                   PERFORM CALCULATE-TRANSACTION-FEES
               WHEN 7
                   PERFORM GENERATE-TRANSACTION-RECEIPT
               WHEN 8
                   PERFORM LOG-TRANSACTION-DETAILS
           END-EVALUATE.
       
       EVALUATE-STEP-RESULT.
           IF STEP-RESULT = 'F'
               MOVE 'E' TO WORKFLOW-STATUS
               PERFORM HANDLE-WORKFLOW-ERROR
           ELSE
               IF CURRENT-STEP = TOTAL-STEPS
                   MOVE 'C' TO WORKFLOW-STATUS
               ELSE
                   ADD 1 TO CURRENT-STEP
               END-IF
           END-IF.

4. Validation Logic

Validation logic ensures data integrity and enforces business constraints throughout the application processing.

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       WORKING-STORAGE SECTION.
       01 VALIDATION-RULES.
           05 MIN-ACCOUNT-BALANCE PIC 9(8)V99 VALUE 0.
           05 MAX-TRANSACTION-AMT PIC 9(8)V99 VALUE 999999.99.
           05 VALID-CUSTOMER-TYPES PIC X(3) VALUE 'PSB'.
           05 VALID-TRANSACTION-TYPES PIC X(4) VALUE 'DWTP'.
       
       01 VALIDATION-RESULTS.
           05 VALIDATION-ERRORS  PIC 9(2) VALUE 0.
           05 ERROR-MESSAGES OCCURS 10 TIMES.
               10 ERROR-CODE     PIC 9(3).
               10 ERROR-MESSAGE  PIC X(50).
       
       01 VALIDATION-FLAGS.
           05 INPUT-VALID        PIC X(1).
               88 INPUT-IS-VALID VALUE 'Y'.
               88 INPUT-INVALID VALUE 'N'.
           05 BALANCE-VALID      PIC X(1).
           05 AMOUNT-VALID       PIC X(1).
           05 TYPE-VALID        PIC X(1).
       
       PROCEDURE DIVISION.
       VALIDATION-LOGIC.
           PERFORM VALIDATE-INPUT-DATA
           PERFORM VALIDATE-BUSINESS-RULES
           PERFORM VALIDATE-TRANSACTION-CONSTRAINTS
           PERFORM FINALIZE-VALIDATION.
       
       VALIDATE-INPUT-DATA.
           MOVE 'Y' TO INPUT-VALID
           MOVE 0 TO VALIDATION-ERRORS
           
           PERFORM VALIDATE-CUSTOMER-ID
           PERFORM VALIDATE-TRANSACTION-AMOUNT
           PERFORM VALIDATE-CUSTOMER-TYPE
           PERFORM VALIDATE-TRANSACTION-TYPE.
       
       VALIDATE-CUSTOMER-ID.
           IF CUSTOMER-ID = ZERO OR CUSTOMER-ID > 999999
               ADD 1 TO VALIDATION-ERRORS
               MOVE 001 TO ERROR-CODE(VALIDATION-ERRORS)
               MOVE 'INVALID CUSTOMER ID' TO ERROR-MESSAGE(VALIDATION-ERRORS)
               MOVE 'N' TO INPUT-VALID
           END-IF.
       
       VALIDATE-TRANSACTION-AMOUNT.
           IF TRANSACTION-AMOUNT <= 0 OR TRANSACTION-AMOUNT > MAX-TRANSACTION-AMT
               ADD 1 TO VALIDATION-ERRORS
               MOVE 002 TO ERROR-CODE(VALIDATION-ERRORS)
               MOVE 'INVALID TRANSACTION AMOUNT' TO ERROR-MESSAGE(VALIDATION-ERRORS)
               MOVE 'N' TO INPUT-VALID
           END-IF.
       
       VALIDATE-BUSINESS-RULES.
           IF INPUT-VALID = 'Y'
               PERFORM CHECK-MINIMUM-BALANCE-RULE
               PERFORM CHECK-CREDIT-LIMIT-RULE
               PERFORM CHECK-TRANSACTION-LIMIT-RULE
           END-IF.
       
       CHECK-MINIMUM-BALANCE-RULE.
           IF ACCOUNT-BALANCE < MINIMUM-BALANCE
               ADD 1 TO VALIDATION-ERRORS
               MOVE 101 TO ERROR-CODE(VALIDATION-ERRORS)
               MOVE 'ACCOUNT BELOW MINIMUM BALANCE' TO ERROR-MESSAGE(VALIDATION-ERRORS)
           END-IF.

Business Logic Patterns

1. Rule-Based Processing

Implement business rules using structured conditional logic and rule tables for maintainable and flexible business logic.

2. State Machine Logic

Use state machines to manage complex business processes with multiple states and transitions.

3. Calculation Logic

Implement complex business calculations with proper error handling and validation.

Best Practices for Business Logic

Modularity: Separate business logic into distinct paragraphs
Maintainability: Use clear naming conventions and documentation
Testability: Design logic for easy testing and validation
Flexibility: Use parameters and configuration for rule changes
Error Handling: Implement comprehensive error handling
Performance: Optimize logic for efficient execution

Common Business Logic Scenarios

Financial Calculations: Interest, fees, and balance calculations
Approval Workflows: Multi-level approval processes
Data Validation: Business rule enforcement
Status Management: State transitions and updates
Pricing Logic: Dynamic pricing calculations
Compliance Rules: Regulatory requirement enforcement

COBOL Business Logic

Understanding Business Logic

Core Components of Business Logic

1. Business Rule Implementation

2. Decision-Making Logic

3. Workflow Control Logic

4. Validation Logic

Business Logic Patterns

1. Rule-Based Processing

2. State Machine Logic

3. Calculation Logic

Best Practices for Business Logic

Common Business Logic Scenarios

Business Rules

Decision Tables

Conditional Logic

Validation Logic

Workflow Control

Error Handling