What is the ORGANIZATION clause used for in COBOL?

The ORGANIZATION clause specifies how records are physically organized and accessed in a file. It determines the file structure (SEQUENTIAL, INDEXED, RELATIVE) and affects how records can be read, written, and updated.

What are the main file organization types in COBOL?

COBOL supports three main organization types: SEQUENTIAL (records stored in sequence), INDEXED (records organized by key fields with indexes), and RELATIVE (records accessed by relative record number).

How does ORGANIZATION affect file processing?

ORGANIZATION determines access methods available (sequential, random, dynamic), performance characteristics, storage requirements, and the types of operations (READ, WRITE, REWRITE, DELETE) that can be performed on the file.

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COBOL ORGANIZATION

The ORGANIZATION clause in COBOL represents comprehensive file structure specification capabilities and sophisticated data organization management functionality within mainframe programming environments, providing advanced file organization mechanisms for data storage, enhanced access method control features, and intelligent record management patterns that enable precise file structure control, complex data organization workflows, and systematic file access requirements while maintaining data integrity, ensuring optimal performance characteristics, and enabling flexible file architectures across enterprise applications requiring specific file organization methods, efficient data access capabilities, and reliable file management throughout sophisticated business data processing scenarios and high-volume file operations.

ORGANIZATION Types and Syntax

File Organization Specifications

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*> Sequential file organization
SELECT CUSTOMER-FILE
    ASSIGN TO "CUSTOMER.DAT"
    ORGANIZATION IS SEQUENTIAL
    ACCESS MODE IS SEQUENTIAL
    FILE STATUS IS WS-FILE-STATUS.
 
*> Indexed file organization
SELECT EMPLOYEE-FILE
    ASSIGN TO "EMPLOYEE.DAT"
    ORGANIZATION IS INDEXED
    ACCESS MODE IS DYNAMIC
    RECORD KEY IS EMP-ID
    ALTERNATE RECORD KEY IS EMP-SSN WITH DUPLICATES
    FILE STATUS IS WS-EMP-STATUS.
 
*> Relative file organization
SELECT INVENTORY-FILE
    ASSIGN TO "INVENTORY.DAT"
    ORGANIZATION IS RELATIVE
    ACCESS MODE IS RANDOM
    RELATIVE KEY IS WS-RECORD-NUMBER
    FILE STATUS IS WS-INV-STATUS.
 
*> Line sequential organization (text files)
SELECT REPORT-FILE
    ASSIGN TO "REPORT.TXT"
    ORGANIZATION IS LINE SEQUENTIAL
    ACCESS MODE IS SEQUENTIAL
    FILE STATUS IS WS-REPORT-STATUS.
 
*> File control examples with different organizations
FILE-CONTROL.
    *> Customer master file - Sequential
    SELECT CUSTOMER-MASTER
        ASSIGN TO "CUSTMAST.DAT"
        ORGANIZATION IS SEQUENTIAL
        ACCESS MODE IS SEQUENTIAL.
    
    *> Product catalog - Indexed by product code
    SELECT PRODUCT-CATALOG
        ASSIGN TO "PRODUCTS.DAT"
        ORGANIZATION IS INDEXED
        ACCESS MODE IS DYNAMIC
        RECORD KEY IS PRODUCT-CODE
        ALTERNATE RECORD KEY IS PRODUCT-NAME
        ALTERNATE RECORD KEY IS SUPPLIER-CODE WITH DUPLICATES.
    
    *> Transaction log - Sequential with time-based access
    SELECT TRANSACTION-LOG
        ASSIGN TO "TRANSLOG.DAT"
        ORGANIZATION IS SEQUENTIAL
        ACCESS MODE IS SEQUENTIAL.
    
    *> Account lookup - Relative file for fast access
    SELECT ACCOUNT-LOOKUP
        ASSIGN TO "ACCOUNTS.DAT"
        ORGANIZATION IS RELATIVE
        ACCESS MODE IS DYNAMIC
        RELATIVE KEY IS WS-ACCOUNT-SLOT.
 
*> Complex organization with multiple access methods
SELECT SALES-HISTORY
    ASSIGN TO "SALESHISTORY.DAT"
    ORGANIZATION IS INDEXED
    ACCESS MODE IS DYNAMIC
    RECORD KEY IS SALES-KEY
    ALTERNATE RECORD KEY IS SALES-DATE-KEY
    ALTERNATE RECORD KEY IS CUSTOMER-KEY WITH DUPLICATES
    ALTERNATE RECORD KEY IS PRODUCT-KEY WITH DUPLICATES
    ALTERNATE RECORD KEY IS REGION-KEY WITH DUPLICATES
    FILE STATUS IS WS-SALES-STATUS.
 
01 SALES-KEY.
   05 SALES-YEAR          PIC 9(4).
   05 SALES-MONTH         PIC 9(2).
   05 SALES-SEQUENCE      PIC 9(6).
 
01 SALES-DATE-KEY         PIC 9(8).
01 CUSTOMER-KEY           PIC X(10).
01 PRODUCT-KEY            PIC X(12).
01 REGION-KEY             PIC X(5).

File Structure

Access Methods

Data Organization

Organization-Specific Operations

Sequential Organization

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*> Sequential file processing
FD CUSTOMER-SEQUENTIAL.
01 CUSTOMER-RECORD.
   05 CUST-ID           PIC 9(8).
   05 CUST-NAME         PIC X(30).
   05 CUST-ADDRESS      PIC X(50).
   05 CUST-BALANCE      PIC S9(9)V99.
 
*> Sequential read processing
OPEN INPUT CUSTOMER-SEQUENTIAL
PERFORM UNTIL END-OF-FILE
    READ CUSTOMER-SEQUENTIAL
        AT END SET END-OF-FILE TO TRUE
        NOT AT END
            PERFORM PROCESS-CUSTOMER
    END-READ
END-PERFORM
CLOSE CUSTOMER-SEQUENTIAL.
 
*> Sequential write processing
OPEN OUTPUT CUSTOMER-SEQUENTIAL
PERFORM VARYING WS-COUNTER FROM 1 BY 1
    UNTIL WS-COUNTER > MAX-CUSTOMERS
    MOVE WS-COUNTER TO CUST-ID
    PERFORM BUILD-CUSTOMER-DATA
    WRITE CUSTOMER-RECORD
    ADD 1 TO RECORDS-WRITTEN
END-PERFORM
CLOSE CUSTOMER-SEQUENTIAL.

Indexed Organization

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*> Indexed file processing
FD EMPLOYEE-INDEXED.
01 EMPLOYEE-RECORD.
   05 EMP-ID            PIC 9(8).
   05 EMP-SSN           PIC 9(9).
   05 EMP-NAME          PIC X(30).
   05 EMP-DEPARTMENT    PIC X(15).
   05 EMP-SALARY        PIC 9(7)V99.
 
*> Random access by key
MOVE 12345678 TO EMP-ID
READ EMPLOYEE-INDEXED
    INVALID KEY
        DISPLAY "Employee not found"
    NOT INVALID KEY
        DISPLAY "Employee: " EMP-NAME
        DISPLAY "Salary: " EMP-SALARY
END-READ.
 
*> Sequential processing of indexed file
START EMPLOYEE-INDEXED
    KEY IS GREATER THAN EMP-ID
    INVALID KEY
        DISPLAY "No records to process"
END-START
 
PERFORM UNTIL END-OF-EMPLOYEES
    READ EMPLOYEE-INDEXED NEXT
        AT END SET END-OF-EMPLOYEES TO TRUE
        NOT AT END
            PERFORM PROCESS-EMPLOYEE
    END-READ
END-PERFORM.

Comprehensive Organization Examples

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IDENTIFICATION DIVISION.
PROGRAM-ID. ORGANIZATION-DEMO.
 
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    *> Sequential customer file
    SELECT CUSTOMER-SEQ-FILE
        ASSIGN TO "CUSTOMERS.SEQ"
        ORGANIZATION IS SEQUENTIAL
        ACCESS MODE IS SEQUENTIAL
        FILE STATUS IS WS-CUST-STATUS.
    
    *> Indexed employee file
    SELECT EMPLOYEE-IDX-FILE
        ASSIGN TO "EMPLOYEES.IDX"
        ORGANIZATION IS INDEXED
        ACCESS MODE IS DYNAMIC
        RECORD KEY IS EMP-ID
        ALTERNATE RECORD KEY IS EMP-DEPT WITH DUPLICATES
        FILE STATUS IS WS-EMP-STATUS.
    
    *> Relative inventory file
    SELECT INVENTORY-REL-FILE
        ASSIGN TO "INVENTORY.REL"
        ORGANIZATION IS RELATIVE
        ACCESS MODE IS DYNAMIC
        RELATIVE KEY IS WS-ITEM-SLOT
        FILE STATUS IS WS-INV-STATUS.
 
DATA DIVISION.
FILE SECTION.
FD CUSTOMER-SEQ-FILE.
01 CUSTOMER-RECORD.
   05 CUST-ID               PIC 9(8).
   05 CUST-NAME             PIC X(30).
   05 CUST-TYPE             PIC X(10).
   05 CUST-BALANCE          PIC S9(9)V99.
 
FD EMPLOYEE-IDX-FILE.
01 EMPLOYEE-RECORD.
   05 EMP-ID                PIC 9(8).
   05 EMP-NAME              PIC X(30).
   05 EMP-DEPT              PIC X(15).
   05 EMP-SALARY            PIC 9(7)V99.
   05 EMP-HIRE-DATE         PIC 9(8).
 
FD INVENTORY-REL-FILE.
01 INVENTORY-RECORD.
   05 ITEM-CODE             PIC X(12).
   05 ITEM-DESCRIPTION      PIC X(40).
   05 QUANTITY-ON-HAND      PIC 9(7).
   05 UNIT-PRICE            PIC 9(7)V99.
 
WORKING-STORAGE SECTION.
01 WS-FILE-STATUS-FIELDS.
   05 WS-CUST-STATUS        PIC XX.
   05 WS-EMP-STATUS         PIC XX.
   05 WS-INV-STATUS         PIC XX.
 
01 WS-CONTROL-FIELDS.
   05 WS-ITEM-SLOT          PIC 9(6).
   05 WS-RECORD-COUNT       PIC 9(6) VALUE 0.
   05 WS-PROCESS-FLAG       PIC X VALUE 'Y'.
 
PROCEDURE DIVISION.
MAIN-ORGANIZATION-DEMO.
    DISPLAY "=== COBOL ORGANIZATION DEMONSTRATION ==="
    
    PERFORM DEMONSTRATE-SEQUENTIAL-ORG
    PERFORM DEMONSTRATE-INDEXED-ORG
    PERFORM DEMONSTRATE-RELATIVE-ORG
    PERFORM DEMONSTRATE-MIXED-OPERATIONS
    
    DISPLAY "=== ORGANIZATION DEMO COMPLETE ==="
    STOP RUN.
 
DEMONSTRATE-SEQUENTIAL-ORG.
    DISPLAY " "
    DISPLAY "=== SEQUENTIAL ORGANIZATION ==="
    
    *> Write sequential records
    OPEN OUTPUT CUSTOMER-SEQ-FILE
    PERFORM VARYING WS-RECORD-COUNT FROM 1 BY 1
        UNTIL WS-RECORD-COUNT > 5
        
        COMPUTE CUST-ID = 1000 + WS-RECORD-COUNT
        STRING "CUSTOMER-" WS-RECORD-COUNT
            DELIMITED BY SIZE INTO CUST-NAME
        MOVE "STANDARD" TO CUST-TYPE
        COMPUTE CUST-BALANCE = WS-RECORD-COUNT * 1000.50
        
        WRITE CUSTOMER-RECORD
        DISPLAY "Written: " CUST-ID " - " CUST-NAME
    END-PERFORM
    CLOSE CUSTOMER-SEQ-FILE
    
    *> Read sequential records
    OPEN INPUT CUSTOMER-SEQ-FILE
    MOVE 0 TO WS-RECORD-COUNT
    PERFORM UNTIL WS-CUST-STATUS = "10"
        READ CUSTOMER-SEQ-FILE
            AT END MOVE "10" TO WS-CUST-STATUS
            NOT AT END
                ADD 1 TO WS-RECORD-COUNT
                DISPLAY "Read: " CUST-ID " - " CUST-NAME
        END-READ
    END-PERFORM
    CLOSE CUSTOMER-SEQ-FILE
    DISPLAY "Sequential processing completed: " WS-RECORD-COUNT " records".
 
DEMONSTRATE-INDEXED-ORG.
    DISPLAY " "
    DISPLAY "=== INDEXED ORGANIZATION ==="
    
    *> Create indexed file with records
    OPEN OUTPUT EMPLOYEE-IDX-FILE
    PERFORM VARYING WS-RECORD-COUNT FROM 1 BY 1
        UNTIL WS-RECORD-COUNT > 8
        
        COMPUTE EMP-ID = 2000 + WS-RECORD-COUNT
        STRING "EMPLOYEE-" WS-RECORD-COUNT
            DELIMITED BY SIZE INTO EMP-NAME
        
        EVALUATE WS-RECORD-COUNT
            WHEN 1 THRU 3 MOVE "FINANCE" TO EMP-DEPT
            WHEN 4 THRU 6 MOVE "IT" TO EMP-DEPT
            WHEN 7 THRU 8 MOVE "SALES" TO EMP-DEPT
        END-EVALUATE
        
        COMPUTE EMP-SALARY = 50000 + (WS-RECORD-COUNT * 2500)
        MOVE 20230101 TO EMP-HIRE-DATE
        
        WRITE EMPLOYEE-RECORD
        DISPLAY "Written indexed: " EMP-ID " - " EMP-NAME " (" EMP-DEPT ")"
    END-PERFORM
    CLOSE EMPLOYEE-IDX-FILE
    
    *> Random access by primary key
    OPEN I-O EMPLOYEE-IDX-FILE
    MOVE 2005 TO EMP-ID
    READ EMPLOYEE-IDX-FILE
        INVALID KEY
            DISPLAY "Employee 2005 not found"
        NOT INVALID KEY
            DISPLAY "Found by key: " EMP-NAME " in " EMP-DEPT
    END-READ
    
    *> Sequential access by alternate key
    MOVE "IT" TO EMP-DEPT
    START EMPLOYEE-IDX-FILE
        KEY IS EQUAL TO EMP-DEPT
        INVALID KEY
            DISPLAY "No IT employees found"
        NOT INVALID KEY
            PERFORM UNTIL WS-EMP-STATUS NOT = "00"
                READ EMPLOYEE-IDX-FILE NEXT
                    AT END MOVE "10" TO WS-EMP-STATUS
                    NOT AT END
                        IF EMP-DEPT = "IT"
                            DISPLAY "IT Employee: " EMP-NAME
                        ELSE
                            MOVE "10" TO WS-EMP-STATUS
                        END-IF
                END-READ
            END-PERFORM
    END-START
    CLOSE EMPLOYEE-IDX-FILE.
 
DEMONSTRATE-RELATIVE-ORG.
    DISPLAY " "
    DISPLAY "=== RELATIVE ORGANIZATION ==="
    
    *> Create relative file
    OPEN OUTPUT INVENTORY-REL-FILE
    PERFORM VARYING WS-RECORD-COUNT FROM 1 BY 1
        UNTIL WS-RECORD-COUNT > 6
        
        COMPUTE WS-ITEM-SLOT = WS-RECORD-COUNT * 10
        STRING "ITEM-" WS-RECORD-COUNT
            DELIMITED BY SIZE INTO ITEM-CODE
        STRING "DESCRIPTION FOR ITEM " WS-RECORD-COUNT
            DELIMITED BY SIZE INTO ITEM-DESCRIPTION
        COMPUTE QUANTITY-ON-HAND = WS-RECORD-COUNT * 100
        COMPUTE UNIT-PRICE = WS-RECORD-COUNT * 15.99
        
        WRITE INVENTORY-RECORD
        DISPLAY "Written to slot " WS-ITEM-SLOT ": " ITEM-CODE
    END-PERFORM
    CLOSE INVENTORY-REL-FILE
    
    *> Random access by relative record number
    OPEN INPUT INVENTORY-REL-FILE
    MOVE 30 TO WS-ITEM-SLOT
    READ INVENTORY-REL-FILE
        INVALID KEY
            DISPLAY "No record at slot 30"
        NOT INVALID KEY
            DISPLAY "Found at slot 30: " ITEM-CODE
            DISPLAY "Quantity: " QUANTITY-ON-HAND
    END-READ
    
    MOVE 50 TO WS-ITEM-SLOT
    READ INVENTORY-REL-FILE
        INVALID KEY
            DISPLAY "No record at slot 50"
        NOT INVALID KEY
            DISPLAY "Found at slot 50: " ITEM-CODE
    END-READ
    CLOSE INVENTORY-REL-FILE.
 
DEMONSTRATE-MIXED-OPERATIONS.
    DISPLAY " "
    DISPLAY "=== MIXED ORGANIZATION OPERATIONS ==="
    
    *> Demonstrate combining different organizations
    DISPLAY "Combining sequential, indexed, and relative access..."
    
    *> Read customer from sequential file
    OPEN INPUT CUSTOMER-SEQ-FILE
    READ CUSTOMER-SEQ-FILE
        AT END DISPLAY "No customers available"
        NOT AT END
            DISPLAY "Processing customer: " CUST-NAME
            
            *> Look up employee by department (indexed)
            OPEN INPUT EMPLOYEE-IDX-FILE
            MOVE "FINANCE" TO EMP-DEPT
            START EMPLOYEE-IDX-FILE
                KEY IS EQUAL TO EMP-DEPT
                NOT INVALID KEY
                    READ EMPLOYEE-IDX-FILE NEXT
                        NOT AT END
                            DISPLAY "Assigned employee: " EMP-NAME
                    END-READ
            END-START
            CLOSE EMPLOYEE-IDX-FILE
            
            *> Check inventory slot (relative)
            OPEN INPUT INVENTORY-REL-FILE
            MOVE 20 TO WS-ITEM-SLOT
            READ INVENTORY-REL-FILE
                NOT INVALID KEY
                    DISPLAY "Available item: " ITEM-CODE
                    DISPLAY "Price: $" UNIT-PRICE
            END-READ
            CLOSE INVENTORY-REL-FILE
    END-READ
    CLOSE CUSTOMER-SEQ-FILE
    
    DISPLAY "Mixed operations completed successfully".

ORGANIZATION Features and Capabilities

Sequential Organization

• Records stored in physical sequence
• Sequential access only
• Efficient for batch processing
• Simple file structure

Indexed Organization

• Key-based record access
• Primary and alternate keys
• Random and sequential access
• Complex search capabilities

Relative Organization

• Record number-based access
• Direct record positioning
• Fast random access
• Fixed-length records

Line Sequential

• Text file processing
• Variable-length records
• Platform-compatible format
• Human-readable content

COBOL Tutorial

COBOL ORGANIZATION

ORGANIZATION Types and Syntax

Organization-Specific Operations

Comprehensive Organization Examples

ORGANIZATION Features and Capabilities

Related Concepts

File Access Methods

Indexed Files

File Status

Related Pages