COBOL SOURCE Clause - Quick Reference

The SOURCE clause in COBOL is used to specify the source or origin of data items. It provides information about where data comes from and how it should be processed.

Primary Use

Define data source and origin specification

Division

DATA DIVISION

Data Type

All data types

Purpose

Data origin and source management

Overview

The SOURCE clause is a COBOL feature that allows you to specify the source or origin of data items. It provides information about where data comes from, which can be useful for data validation, integration purposes, and maintaining data lineage. The SOURCE clause helps document and manage data flow between different systems and components.

Syntax

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01 data-name [PICTURE clause] [SOURCE source-specification].
 
* Examples of SOURCE specifications:
SOURCE IS "EXTERNAL-SYSTEM"
SOURCE IS "DATABASE-TABLE"
SOURCE IS "FILE-INPUT"
SOURCE IS "USER-INPUT"
SOURCE IS "CALCULATED"

Practical Examples

Basic SOURCE Clause Usage

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* Basic SOURCE clause examples
IDENTIFICATION DIVISION.
PROGRAM-ID. SOURCE-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* Customer data from external system
01  CUSTOMER-DATA.
    05  CUSTOMER-ID          PIC X(10) SOURCE IS "EXTERNAL-SYSTEM".
    05  CUSTOMER-NAME        PIC X(30) SOURCE IS "EXTERNAL-SYSTEM".
    05  CUSTOMER-BALANCE     PIC 9(8)V99 SOURCE IS "DATABASE".
 
* Transaction data from file input
01  TRANSACTION-DATA.
    05  TRANSACTION-ID       PIC X(15) SOURCE IS "FILE-INPUT".
    05  TRANSACTION-AMOUNT   PIC 9(8)V99 SOURCE IS "FILE-INPUT".
    05  TRANSACTION-DATE     PIC X(8) SOURCE IS "FILE-INPUT".
 
* Calculated fields
01  CALCULATED-FIELDS.
    05  TOTAL-AMOUNT         PIC 9(10)V99 SOURCE IS "CALCULATED".
    05  AVERAGE-BALANCE      PIC 9(8)V99 SOURCE IS "CALCULATED".
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    DISPLAY "Customer ID source: EXTERNAL-SYSTEM"
    DISPLAY "Transaction ID source: FILE-INPUT"
    DISPLAY "Total amount source: CALCULATED"
    STOP RUN.

Explanation: This example demonstrates basic usage of the SOURCE clause to specify the origin of different data items. CUSTOMER-DATA fields are marked as coming from an external system, TRANSACTION-DATA fields are from file input, and CALCULATED-FIELDS are marked as computed values. This helps document data lineage and origins.

SOURCE with Data Integration

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* SOURCE clause for data integration scenarios
IDENTIFICATION DIVISION.
PROGRAM-ID. DATA-INTEGRATION-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* Legacy system data
01  LEGACY-CUSTOMER.
    05  LEGACY-CUST-ID       PIC X(8) SOURCE IS "LEGACY-SYSTEM".
    05  LEGACY-CUST-NAME     PIC X(25) SOURCE IS "LEGACY-SYSTEM".
    05  LEGACY-ACCOUNT-NO    PIC 9(10) SOURCE IS "LEGACY-SYSTEM".
 
* Modern system data
01  MODERN-CUSTOMER.
    05  MODERN-CUST-ID       PIC X(10) SOURCE IS "MODERN-SYSTEM".
    05  MODERN-CUST-NAME     PIC X(30) SOURCE IS "MODERN-SYSTEM".
    05  MODERN-ACCOUNT-NO    PIC X(12) SOURCE IS "MODERN-SYSTEM".
 
* Consolidated customer data
01  CONSOLIDATED-CUSTOMER.
    05  CONSOLIDATED-ID      PIC X(10) SOURCE IS "CONSOLIDATED".
    05  CONSOLIDATED-NAME    PIC X(30) SOURCE IS "CONSOLIDATED".
    05  CONSOLIDATED-ACCOUNT PIC X(12) SOURCE IS "CONSOLIDATED".
    05  DATA-SOURCE-FLAG     PIC X(1) SOURCE IS "CONSOLIDATED".
        * L = Legacy, M = Modern, C = Combined
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Process legacy system data
    MOVE LEGACY-CUST-ID TO CONSOLIDATED-ID
    MOVE LEGACY-CUST-NAME TO CONSOLIDATED-NAME
    MOVE LEGACY-ACCOUNT-NO TO CONSOLIDATED-ACCOUNT
    MOVE 'L' TO DATA-SOURCE-FLAG
    
    DISPLAY "Processing data from: " DATA-SOURCE-FLAG
    DISPLAY "Customer ID: " CONSOLIDATED-ID
    DISPLAY "Customer Name: " CONSOLIDATED-NAME
    DISPLAY "Account Number: " CONSOLIDATED-ACCOUNT
    
    STOP RUN.

Explanation: This example shows how the SOURCE clause can be used in data integration scenarios. Different customer data structures are marked with their respective sources (LEGACY-SYSTEM, MODERN-SYSTEM, CONSOLIDATED). The DATA-SOURCE-FLAG tracks which system the data originated from, helping maintain data lineage during integration processes.

SOURCE with Data Validation

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* SOURCE clause for data validation
IDENTIFICATION DIVISION.
PROGRAM-ID. DATA-VALIDATION-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* User input data
01  USER-INPUT-DATA.
    05  USER-NAME            PIC X(20) SOURCE IS "USER-INPUT".
    05  USER-AGE             PIC 99 SOURCE IS "USER-INPUT".
    05  USER-EMAIL           PIC X(50) SOURCE IS "USER-INPUT".
 
* Database reference data
01  REFERENCE-DATA.
    05  VALID-AGE-MIN        PIC 99 SOURCE IS "DATABASE" VALUE 18.
    05  VALID-AGE-MAX        PIC 99 SOURCE IS "DATABASE" VALUE 120.
    05  EMAIL-PATTERN        PIC X(50) SOURCE IS "DATABASE" 
        VALUE "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$".
 
* Validation results
01  VALIDATION-RESULTS.
    05  NAME-VALID           PIC X(1) SOURCE IS "VALIDATION".
    05  AGE-VALID            PIC X(1) SOURCE IS "VALIDATION".
    05  EMAIL-VALID          PIC X(1) SOURCE IS "VALIDATION".
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Validate user name (not empty)
    IF USER-NAME = SPACES
        MOVE 'N' TO NAME-VALID
    ELSE
        MOVE 'Y' TO NAME-VALID
    END-IF
    
    * Validate age range
    IF USER-AGE >= VALID-AGE-MIN AND USER-AGE <= VALID-AGE-MAX
        MOVE 'Y' TO AGE-VALID
    ELSE
        MOVE 'N' TO AGE-VALID
    END-IF
    
    * Validate email format (simplified)
    IF USER-EMAIL CONTAINS '@' AND USER-EMAIL CONTAINS '.'
        MOVE 'Y' TO EMAIL-VALID
    ELSE
        MOVE 'N' TO EMAIL-VALID
    END-IF
    
    * Display validation results
    DISPLAY "Validation Results:"
    DISPLAY "Name valid: " NAME-VALID
    DISPLAY "Age valid: " AGE-VALID
    DISPLAY "Email valid: " EMAIL-VALID
    
    STOP RUN.

Explanation: This example demonstrates how the SOURCE clause can be used for data validation. User input data is marked with SOURCE IS "USER-INPUT", reference data from the database is marked with SOURCE IS "DATABASE", and validation results are marked with SOURCE IS "VALIDATION". This helps track data flow and maintain clear separation between input data, reference data, and validation results.

SOURCE with Financial Data Processing

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* SOURCE clause for financial data processing
IDENTIFICATION DIVISION.
PROGRAM-ID. FINANCIAL-DATA-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* Transaction data from multiple sources
01  TRANSACTION-RECORD.
    05  TRANSACTION-ID       PIC X(15) SOURCE IS "TRANSACTION-SYSTEM".
    05  ACCOUNT-NUMBER       PIC X(12) SOURCE IS "ACCOUNT-SYSTEM".
    05  TRANSACTION-AMOUNT   PIC 9(8)V99 SOURCE IS "TRANSACTION-SYSTEM".
    05  TRANSACTION-DATE     PIC X(8) SOURCE IS "TRANSACTION-SYSTEM".
    05  TRANSACTION-TYPE     PIC X(2) SOURCE IS "TRANSACTION-SYSTEM".
 
* Account reference data
01  ACCOUNT-REFERENCE.
    05  REF-ACCOUNT-NUMBER   PIC X(12) SOURCE IS "ACCOUNT-SYSTEM".
    05  ACCOUNT-TYPE         PIC X(1) SOURCE IS "ACCOUNT-SYSTEM".
    05  ACCOUNT-LIMIT        PIC 9(8)V99 SOURCE IS "ACCOUNT-SYSTEM".
    05  ACCOUNT-STATUS       PIC X(1) SOURCE IS "ACCOUNT-SYSTEM".
 
* Calculated financial data
01  FINANCIAL-CALCULATIONS.
    05  DAILY-TOTAL          PIC 9(10)V99 SOURCE IS "CALCULATED".
    05  MONTHLY-TOTAL        PIC 9(12)V99 SOURCE IS "CALCULATED".
    05  AVERAGE-TRANSACTION  PIC 9(8)V99 SOURCE IS "CALCULATED".
    05  TRANSACTION-COUNT    PIC 9(6) SOURCE IS "CALCULATED".
 
* Audit trail data
01  AUDIT-INFORMATION.
    05  PROCESSING-DATE      PIC X(8) SOURCE IS "SYSTEM-DATE".
    05  PROCESSING-TIME      PIC X(6) SOURCE IS "SYSTEM-TIME".
    05  USER-ID              PIC X(8) SOURCE IS "USER-SESSION".
    05  BATCH-NUMBER         PIC X(10) SOURCE IS "BATCH-SYSTEM".
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Process transaction data
    DISPLAY "Processing transaction from: TRANSACTION-SYSTEM"
    DISPLAY "Account data from: ACCOUNT-SYSTEM"
    DISPLAY "Calculations: CALCULATED"
    DISPLAY "Audit info from: SYSTEM-DATE, SYSTEM-TIME, USER-SESSION"
    
    * Simulate data processing
    MOVE 1000.00 TO DAILY-TOTAL
    MOVE 25000.00 TO MONTHLY-TOTAL
    MOVE 125.00 TO AVERAGE-TRANSACTION
    MOVE 20 TO TRANSACTION-COUNT
    
    DISPLAY "Daily Total: " DAILY-TOTAL
    DISPLAY "Monthly Total: " MONTHLY-TOTAL
    DISPLAY "Average Transaction: " AVERAGE-TRANSACTION
    DISPLAY "Transaction Count: " TRANSACTION-COUNT
    
    STOP RUN.

Explanation: This example shows how the SOURCE clause can be used in financial data processing. Different data elements are marked with their respective sources: transaction data from TRANSACTION-SYSTEM, account reference data from ACCOUNT-SYSTEM, calculated financial data as CALCULATED, and audit information from various system sources. This helps maintain data lineage and provides clear documentation of data origins in financial processing applications.

Best Practices and Considerations

Important Considerations

Use consistent source naming conventions across your application
Document source specifications clearly for maintenance purposes
Consider using SOURCE for data lineage and audit trails
Validate that source specifications are accurate and up-to-date
Use SOURCE in conjunction with other data definition clauses

Advantages

Provides clear data lineage documentation
Helps with data validation and processing
Supports data integration scenarios
Improves code maintainability
Facilitates audit trail creation

Limitations

Requires consistent naming conventions
May not be supported in all COBOL implementations
Adds complexity to data definitions
Requires maintenance when data sources change
May impact code readability if overused

Best Practices

• Use descriptive and consistent source names
• Document source specifications in program comments
• Update source specifications when data sources change
• Use SOURCE for critical data lineage requirements
• Consider using SOURCE in data integration projects

Test Your Knowledge

1. What is the primary purpose of the SOURCE clause in COBOL?

To specify source code location
To define data source and origin specification
To source programs
To source files

2. In which COBOL division is the SOURCE clause typically used?

IDENTIFICATION DIVISION
ENVIRONMENT DIVISION
DATA DIVISION
PROCEDURE DIVISION

3. What does the SOURCE clause control in data definition?

Data validation
Data source and origin specification
Data type
Data format

4. Can SOURCE be used with all data types?

Yes, with all data types
No, only with numeric types
No, only with character types
Only with specific data types

5. What is the relationship between SOURCE and data processing?

They are unrelated
SOURCE specifies data origin for processing
SOURCE only affects display
SOURCE is for validation only

COBOL Tutorial

COBOL SOURCE Clause - Quick Reference

Primary Use

Division

Data Type

Purpose

Overview

Syntax

Practical Examples

Basic SOURCE Clause Usage

SOURCE with Data Integration

SOURCE with Data Validation

SOURCE with Financial Data Processing

Best Practices and Considerations

Important Considerations

Advantages

Limitations

Best Practices

Test Your Knowledge

Related Concepts

SOURCE-COMPUTER Clause

Data Integration

Data Lineage

Data Validation

System Integration

Related Pages

COBOL Tutorial

COBOL SOURCE Clause - Quick Reference

Primary Use

Division

Data Type

Purpose

Overview

Syntax

Practical Examples

Basic SOURCE Clause Usage

SOURCE with Data Integration

SOURCE with Data Validation

SOURCE with Financial Data Processing

Best Practices and Considerations

Important Considerations

Advantages

Limitations

Best Practices

Test Your Knowledge

Frequently Asked Questions

Related Concepts

SOURCE-COMPUTER Clause

Data Integration

Data Lineage

Data Validation

System Integration

Related Pages