The INVALID KEY clause represents a critical error handling mechanism within COBOL file processing operations, providing comprehensive exception management for key-related failures in indexed and relative file operations. This clause embodies the principles of robust error handling by supporting graceful failure recovery, detailed error processing, and comprehensive exception management while maintaining program stability, ensuring data integrity, and facilitating reliable file operations across enterprise applications requiring sophisticated error recovery, comprehensive key validation, and resilient data processing with predictable error handling and optimized recovery procedures.
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667*> READ with INVALID KEY READ file-name RECORD KEY IS key-field INVALID KEY imperative-statements NOT INVALID KEY imperative-statements END-READ *> WRITE with INVALID KEY WRITE record-name INVALID KEY imperative-statements NOT INVALID KEY imperative-statements END-WRITE *> REWRITE with INVALID KEY REWRITE record-name INVALID KEY imperative-statements NOT INVALID KEY imperative-statements END-REWRITE *> DELETE with INVALID KEY DELETE file-name RECORD INVALID KEY imperative-statements NOT INVALID KEY imperative-statements END-DELETE *> START with INVALID KEY START file-name KEY IS EQUAL TO key-field INVALID KEY imperative-statements NOT INVALID KEY imperative-statements END-START *> Basic examples 01 WS-FILE-STATUS PIC XX. 88 FILE-OK VALUE "00". 88 RECORD-NOT-FOUND VALUE "23". 88 DUPLICATE-KEY VALUE "22". PROCEDURE DIVISION. *> Read with error handling READ CUSTOMER-FILE KEY IS CUSTOMER-ID INVALID KEY DISPLAY "Customer not found: " CUSTOMER-ID PERFORM ERROR-PROCESSING NOT INVALID KEY PERFORM PROCESS-CUSTOMER-RECORD END-READ *> Write with duplicate key handling WRITE CUSTOMER-RECORD INVALID KEY DISPLAY "Duplicate customer ID: " CUSTOMER-ID PERFORM DUPLICATE-KEY-HANDLING NOT INVALID KEY DISPLAY "Customer record added successfully" END-WRITE
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699IDENTIFICATION DIVISION. PROGRAM-ID. INVALID-KEY-DEMO. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT CUSTOMER-FILE ASSIGN TO "CUSTOMER.DAT" ORGANIZATION IS INDEXED ACCESS MODE IS DYNAMIC RECORD KEY IS CUST-ID ALTERNATE RECORD KEY IS CUST-EMAIL WITH DUPLICATES FILE STATUS IS WS-CUST-STATUS. SELECT PRODUCT-FILE ASSIGN TO "PRODUCT.DAT" ORGANIZATION IS INDEXED ACCESS MODE IS DYNAMIC RECORD KEY IS PROD-ID ALTERNATE RECORD KEY IS PROD-NAME FILE STATUS IS WS-PROD-STATUS. SELECT ORDER-FILE ASSIGN TO "ORDERS.DAT" ORGANIZATION IS RELATIVE ACCESS MODE IS DYNAMIC RELATIVE KEY IS WS-ORDER-KEY FILE STATUS IS WS-ORDER-STATUS. DATA DIVISION. FILE SECTION. FD CUSTOMER-FILE. 01 CUSTOMER-RECORD. 05 CUST-ID PIC X(8). 05 CUST-NAME PIC X(30). 05 CUST-EMAIL PIC X(50). 05 CUST-PHONE PIC X(15). 05 CUST-CREDIT-LIMIT PIC 9(7)V99. 05 CUST-BALANCE PIC S9(7)V99. 05 CUST-STATUS PIC X(10). FD PRODUCT-FILE. 01 PRODUCT-RECORD. 05 PROD-ID PIC X(10). 05 PROD-NAME PIC X(40). 05 PROD-CATEGORY PIC X(20). 05 PROD-PRICE PIC 9(6)V99. 05 PROD-QUANTITY PIC 9(6). 05 PROD-REORDER-LEVEL PIC 9(4). FD ORDER-FILE. 01 ORDER-RECORD. 05 ORDER-ID PIC 9(8). 05 ORDER-CUST-ID PIC X(8). 05 ORDER-DATE PIC 9(8). 05 ORDER-TOTAL PIC 9(8)V99. 05 ORDER-STATUS PIC X(10). WORKING-STORAGE SECTION. 01 WS-FILE-STATUS-FIELDS. 05 WS-CUST-STATUS PIC XX. 88 CUST-OK VALUE "00". 88 CUST-NOT-FOUND VALUE "23". 88 CUST-DUPLICATE VALUE "22". 88 CUST-EOF VALUE "10". 05 WS-PROD-STATUS PIC XX. 88 PROD-OK VALUE "00". 88 PROD-NOT-FOUND VALUE "23". 88 PROD-DUPLICATE VALUE "22". 05 WS-ORDER-STATUS PIC XX. 88 ORDER-OK VALUE "00". 88 ORDER-NOT-FOUND VALUE "23". 01 WS-CONTROL-FIELDS. 05 WS-ORDER-KEY PIC 9(8). 05 WS-OPERATION-TYPE PIC X(10). 05 WS-ERROR-COUNT PIC 9(4) VALUE 0. 05 WS-SUCCESS-COUNT PIC 9(4) VALUE 0. 05 WS-PROCESSING-FLAG PIC X VALUE 'N'. 88 PROCESSING-COMPLETE VALUE 'Y'. 01 WS-SEARCH-FIELDS. 05 WS-SEARCH-CUST-ID PIC X(8). 05 WS-SEARCH-EMAIL PIC X(50). 05 WS-SEARCH-PROD-ID PIC X(10). 05 WS-SEARCH-PROD-NAME PIC X(40). 01 WS-VALIDATION-FIELDS. 05 WS-VALIDATION-RESULT PIC X VALUE 'N'. 88 VALIDATION-PASSED VALUE 'Y'. 88 VALIDATION-FAILED VALUE 'N'. 05 WS-ERROR-MESSAGE PIC X(100). 01 WS-TEST-DATA. 05 WS-TEST-CUSTOMER. 10 WS-TEST-CUST-ID PIC X(8) VALUE "CUST0001". 10 WS-TEST-CUST-NAME PIC X(30) VALUE "JOHN SMITH". 10 WS-TEST-CUST-EMAIL PIC X(50) VALUE "john.smith@email.com". 05 WS-TEST-PRODUCT. 10 WS-TEST-PROD-ID PIC X(10) VALUE "PROD001". 10 WS-TEST-PROD-NAME PIC X(40) VALUE "PREMIUM WIDGET". PROCEDURE DIVISION. MAIN-PROCESSING. PERFORM OPEN-FILES PERFORM DEMONSTRATE-READ-OPERATIONS PERFORM DEMONSTRATE-WRITE-OPERATIONS PERFORM DEMONSTRATE-UPDATE-OPERATIONS PERFORM DEMONSTRATE-DELETE-OPERATIONS PERFORM DEMONSTRATE-START-OPERATIONS PERFORM DEMONSTRATE-ERROR-RECOVERY PERFORM CLOSE-FILES PERFORM DISPLAY-STATISTICS STOP RUN. OPEN-FILES. OPEN I-O CUSTOMER-FILE IF NOT CUST-OK DISPLAY "Error opening customer file: " WS-CUST-STATUS STOP RUN END-IF OPEN I-O PRODUCT-FILE IF NOT PROD-OK DISPLAY "Error opening product file: " WS-PROD-STATUS STOP RUN END-IF OPEN I-O ORDER-FILE IF NOT ORDER-OK DISPLAY "Error opening order file: " WS-ORDER-STATUS STOP RUN END-IF DISPLAY "All files opened successfully". DEMONSTRATE-READ-OPERATIONS. DISPLAY "=== READ OPERATIONS WITH INVALID KEY ===" *> Test reading existing customer MOVE WS-TEST-CUST-ID TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Customer not found: " CUST-ID PERFORM CREATE-SAMPLE-CUSTOMER NOT INVALID KEY DISPLAY "Customer found: " CUST-NAME ADD 1 TO WS-SUCCESS-COUNT END-READ *> Test reading non-existent customer MOVE "INVALID1" TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Expected: Customer " CUST-ID " not found" ADD 1 TO WS-ERROR-COUNT MOVE "Customer lookup failed" TO WS-ERROR-MESSAGE PERFORM LOG-ERROR NOT INVALID KEY DISPLAY "Unexpected: Found customer " CUST-NAME END-READ *> Test reading by alternate key (email) MOVE WS-TEST-CUST-EMAIL TO CUST-EMAIL READ CUSTOMER-FILE KEY IS CUST-EMAIL INVALID KEY DISPLAY "No customer with email: " CUST-EMAIL ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Customer found by email: " CUST-NAME ADD 1 TO WS-SUCCESS-COUNT END-READ DISPLAY SPACES. CREATE-SAMPLE-CUSTOMER. MOVE WS-TEST-CUST-ID TO CUST-ID MOVE WS-TEST-CUST-NAME TO CUST-NAME MOVE WS-TEST-CUST-EMAIL TO CUST-EMAIL MOVE "555-1234" TO CUST-PHONE MOVE 5000.00 TO CUST-CREDIT-LIMIT MOVE 0.00 TO CUST-BALANCE MOVE "ACTIVE" TO CUST-STATUS WRITE CUSTOMER-RECORD INVALID KEY DISPLAY "Error creating sample customer: " CUST-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Sample customer created: " CUST-ID ADD 1 TO WS-SUCCESS-COUNT END-WRITE. DEMONSTRATE-WRITE-OPERATIONS. DISPLAY "=== WRITE OPERATIONS WITH INVALID KEY ===" *> Test writing new product MOVE WS-TEST-PROD-ID TO PROD-ID MOVE WS-TEST-PROD-NAME TO PROD-NAME MOVE "ELECTRONICS" TO PROD-CATEGORY MOVE 99.99 TO PROD-PRICE MOVE 100 TO PROD-QUANTITY MOVE 10 TO PROD-REORDER-LEVEL WRITE PRODUCT-RECORD INVALID KEY DISPLAY "Product already exists: " PROD-ID ADD 1 TO WS-ERROR-COUNT PERFORM HANDLE-DUPLICATE-PRODUCT NOT INVALID KEY DISPLAY "Product added successfully: " PROD-ID ADD 1 TO WS-SUCCESS-COUNT END-WRITE *> Test writing duplicate product (should fail) WRITE PRODUCT-RECORD INVALID KEY DISPLAY "Expected: Duplicate product detected: " PROD-ID ADD 1 TO WS-ERROR-COUNT IF PROD-DUPLICATE DISPLAY "Confirmed: Duplicate key error" ELSE DISPLAY "Unexpected error code: " WS-PROD-STATUS END-IF NOT INVALID KEY DISPLAY "Unexpected: Duplicate write succeeded" END-WRITE *> Test writing to relative file MOVE 1 TO WS-ORDER-KEY MOVE 12345678 TO ORDER-ID MOVE WS-TEST-CUST-ID TO ORDER-CUST-ID MOVE FUNCTION CURRENT-DATE(1:8) TO ORDER-DATE MOVE 299.99 TO ORDER-TOTAL MOVE "PENDING" TO ORDER-STATUS WRITE ORDER-RECORD INVALID KEY DISPLAY "Error writing order at position: " WS-ORDER-KEY ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Order written successfully at position: " WS-ORDER-KEY ADD 1 TO WS-SUCCESS-COUNT END-WRITE DISPLAY SPACES. HANDLE-DUPLICATE-PRODUCT. DISPLAY "Handling duplicate product scenario..." *> Read existing product to compare READ PRODUCT-FILE KEY IS PROD-ID INVALID KEY DISPLAY "Unexpected: Product not found after duplicate error" NOT INVALID KEY DISPLAY "Existing product: " PROD-NAME DISPLAY "Attempting to add: " WS-TEST-PROD-NAME *> Could offer update option here DISPLAY "Consider using REWRITE to update existing product" END-READ. DEMONSTRATE-UPDATE-OPERATIONS. DISPLAY "=== UPDATE OPERATIONS WITH INVALID KEY ===" *> Test rewriting existing customer MOVE WS-TEST-CUST-ID TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Cannot update - customer not found: " CUST-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY *> Update customer information MOVE "JOHN Q. SMITH" TO CUST-NAME MOVE "john.q.smith@email.com" TO CUST-EMAIL ADD 1000.00 TO CUST-CREDIT-LIMIT REWRITE CUSTOMER-RECORD INVALID KEY DISPLAY "Error updating customer: " CUST-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Customer updated successfully: " CUST-ID ADD 1 TO WS-SUCCESS-COUNT END-REWRITE END-READ *> Test rewriting non-existent product MOVE "NOEXIST" TO PROD-ID MOVE "NON-EXISTENT PRODUCT" TO PROD-NAME REWRITE PRODUCT-RECORD INVALID KEY DISPLAY "Expected: Cannot rewrite non-existent product" ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Unexpected: Rewrite succeeded for non-existent product" END-REWRITE DISPLAY SPACES. DEMONSTRATE-DELETE-OPERATIONS. DISPLAY "=== DELETE OPERATIONS WITH INVALID KEY ===" *> Test deleting existing product MOVE WS-TEST-PROD-ID TO PROD-ID DELETE PRODUCT-FILE INVALID KEY DISPLAY "Cannot delete - product not found: " PROD-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Product deleted successfully: " PROD-ID ADD 1 TO WS-SUCCESS-COUNT END-DELETE *> Test deleting non-existent product (should fail) DELETE PRODUCT-FILE INVALID KEY DISPLAY "Expected: Cannot delete non-existent product" ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Unexpected: Delete succeeded for non-existent product" END-DELETE *> Test deleting from relative file MOVE 1 TO WS-ORDER-KEY DELETE ORDER-FILE INVALID KEY DISPLAY "Cannot delete order at position: " WS-ORDER-KEY ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Order deleted successfully from position: " WS-ORDER-KEY ADD 1 TO WS-SUCCESS-COUNT END-DELETE DISPLAY SPACES. DEMONSTRATE-START-OPERATIONS. DISPLAY "=== START OPERATIONS WITH INVALID KEY ===" *> Test START operation for sequential reading MOVE WS-TEST-CUST-ID TO CUST-ID START CUSTOMER-FILE KEY IS GREATER THAN CUST-ID INVALID KEY DISPLAY "No customers found after: " CUST-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Positioned for reading after: " CUST-ID ADD 1 TO WS-SUCCESS-COUNT PERFORM READ-NEXT-CUSTOMERS END-START *> Test START with non-existent key range MOVE "ZZZZZZZZ" TO CUST-ID START CUSTOMER-FILE KEY IS GREATER THAN CUST-ID INVALID KEY DISPLAY "Expected: No customers after " CUST-ID ADD 1 TO WS-ERROR-COUNT NOT INVALID KEY DISPLAY "Unexpected: Found customers after " CUST-ID END-START DISPLAY SPACES. READ-NEXT-CUSTOMERS. PERFORM 3 TIMES READ CUSTOMER-FILE NEXT RECORD AT END DISPLAY "Reached end of customer file" EXIT PERFORM NOT AT END DISPLAY "Next customer: " CUST-ID " - " CUST-NAME END-READ END-PERFORM. DEMONSTRATE-ERROR-RECOVERY. DISPLAY "=== ERROR RECOVERY DEMONSTRATIONS ===" PERFORM ROBUST-CUSTOMER-LOOKUP PERFORM SAFE-PRODUCT-UPDATE PERFORM BATCH-PROCESSING-WITH-ERRORS DISPLAY SPACES. ROBUST-CUSTOMER-LOOKUP. DISPLAY "Robust Customer Lookup with Error Recovery:" MOVE "LOOKUP01" TO WS-SEARCH-CUST-ID MOVE WS-SEARCH-CUST-ID TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Primary lookup failed for: " CUST-ID PERFORM ALTERNATIVE-CUSTOMER-SEARCH NOT INVALID KEY DISPLAY "Customer found: " CUST-NAME PERFORM PROCESS-CUSTOMER-DATA END-READ. ALTERNATIVE-CUSTOMER-SEARCH. DISPLAY "Attempting alternative search methods..." *> Try partial key search MOVE WS-SEARCH-CUST-ID(1:4) TO CUST-ID(1:4) MOVE LOW-VALUES TO CUST-ID(5:4) START CUSTOMER-FILE KEY IS GREATER THAN OR EQUAL TO CUST-ID INVALID KEY DISPLAY "No customers found with similar ID pattern" PERFORM CREATE-CUSTOMER-NOT-FOUND-LOG NOT INVALID KEY DISPLAY "Found similar customer ID pattern" PERFORM DISPLAY-SIMILAR-CUSTOMERS END-START. CREATE-CUSTOMER-NOT-FOUND-LOG. DISPLAY "Creating customer not found log entry..." MOVE "CUSTOMER NOT FOUND" TO WS-ERROR-MESSAGE PERFORM LOG-ERROR. DISPLAY-SIMILAR-CUSTOMERS. DISPLAY "Similar customers found:" PERFORM 5 TIMES READ CUSTOMER-FILE NEXT RECORD AT END EXIT PERFORM NOT AT END IF CUST-ID(1:4) = WS-SEARCH-CUST-ID(1:4) DISPLAY " Similar: " CUST-ID " - " CUST-NAME ELSE EXIT PERFORM END-IF END-READ END-PERFORM. SAFE-PRODUCT-UPDATE. DISPLAY "Safe Product Update with Validation:" MOVE "PROD002" TO PROD-ID *> First read to verify existence READ PRODUCT-FILE KEY IS PROD-ID INVALID KEY DISPLAY "Product not found for update: " PROD-ID PERFORM CREATE-NEW-PRODUCT-OPTION NOT INVALID KEY DISPLAY "Product found, proceeding with update" PERFORM VALIDATE-UPDATE-DATA IF VALIDATION-PASSED PERFORM EXECUTE-SAFE-UPDATE ELSE DISPLAY "Update validation failed: " WS-ERROR-MESSAGE END-IF END-READ. CREATE-NEW-PRODUCT-OPTION. DISPLAY "Product doesn't exist - offering creation option" MOVE "NEW PRODUCT" TO PROD-NAME MOVE "GENERAL" TO PROD-CATEGORY MOVE 19.99 TO PROD-PRICE MOVE 50 TO PROD-QUANTITY MOVE 5 TO PROD-REORDER-LEVEL WRITE PRODUCT-RECORD INVALID KEY DISPLAY "Error creating new product: " PROD-ID NOT INVALID KEY DISPLAY "New product created: " PROD-ID END-WRITE. VALIDATE-UPDATE-DATA. SET VALIDATION-PASSED TO TRUE *> Validate price is reasonable IF PROD-PRICE < 0 OR PROD-PRICE > 99999.99 SET VALIDATION-FAILED TO TRUE MOVE "Invalid price range" TO WS-ERROR-MESSAGE END-IF *> Validate quantity is positive IF PROD-QUANTITY < 0 SET VALIDATION-FAILED TO TRUE MOVE "Negative quantity not allowed" TO WS-ERROR-MESSAGE END-IF. EXECUTE-SAFE-UPDATE. *> Make backup of original values (in real application) ADD 10 TO PROD-QUANTITY ADD 5.00 TO PROD-PRICE REWRITE PRODUCT-RECORD INVALID KEY DISPLAY "Update failed for product: " PROD-ID *> Restore original values here NOT INVALID KEY DISPLAY "Product updated successfully: " PROD-ID END-REWRITE. BATCH-PROCESSING-WITH-ERRORS. DISPLAY "Batch Processing with Error Handling:" MOVE 0 TO WS-ERROR-COUNT MOVE 0 TO WS-SUCCESS-COUNT *> Process multiple operations with error tracking PERFORM PROCESS-BATCH-CUSTOMER PERFORM PROCESS-BATCH-PRODUCT PERFORM PROCESS-BATCH-ORDER DISPLAY "Batch processing completed:" DISPLAY " Successful operations: " WS-SUCCESS-COUNT DISPLAY " Failed operations: " WS-ERROR-COUNT. PROCESS-BATCH-CUSTOMER. MOVE "BATCH001" TO CUST-ID MOVE "BATCH CUSTOMER 1" TO CUST-NAME MOVE "batch1@test.com" TO CUST-EMAIL WRITE CUSTOMER-RECORD INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Batch customer write failed: " CUST-ID NOT INVALID KEY ADD 1 TO WS-SUCCESS-COUNT END-WRITE. PROCESS-BATCH-PRODUCT. MOVE "BATCH001" TO PROD-ID MOVE "BATCH PRODUCT 1" TO PROD-NAME WRITE PRODUCT-RECORD INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Batch product write failed: " PROD-ID NOT INVALID KEY ADD 1 TO WS-SUCCESS-COUNT END-WRITE. PROCESS-BATCH-ORDER. MOVE 2 TO WS-ORDER-KEY MOVE 87654321 TO ORDER-ID WRITE ORDER-RECORD INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Batch order write failed at position: " WS-ORDER-KEY NOT INVALID KEY ADD 1 TO WS-SUCCESS-COUNT END-WRITE. PROCESS-CUSTOMER-DATA. DISPLAY "Processing customer: " CUST-NAME DISPLAY "Credit limit: $" CUST-CREDIT-LIMIT DISPLAY "Current balance: $" CUST-BALANCE. LOG-ERROR. DISPLAY "ERROR LOG: " WS-ERROR-MESSAGE *> In real application, write to error log file. CLOSE-FILES. CLOSE CUSTOMER-FILE CLOSE PRODUCT-FILE CLOSE ORDER-FILE DISPLAY "All files closed successfully". DISPLAY-STATISTICS. DISPLAY "=== PROCESSING STATISTICS ===" DISPLAY "Total successful operations: " WS-SUCCESS-COUNT DISPLAY "Total failed operations: " WS-ERROR-COUNT IF WS-ERROR-COUNT > 0 COMPUTE WS-ORDER-KEY = (WS-ERROR-COUNT * 100) / (WS-SUCCESS-COUNT + WS-ERROR-COUNT) DISPLAY "Error rate: " WS-ORDER-KEY "%" ELSE DISPLAY "Error rate: 0%" END-IF. *> Advanced error handling patterns TRANSACTION-ROLLBACK-SIMULATION. DISPLAY "=== TRANSACTION ROLLBACK SIMULATION ===" *> Simulate transaction with multiple operations PERFORM BEGIN-TRANSACTION PERFORM TRANSACTION-OPERATION-1 PERFORM TRANSACTION-OPERATION-2 PERFORM TRANSACTION-OPERATION-3 IF WS-ERROR-COUNT > 0 PERFORM ROLLBACK-TRANSACTION ELSE PERFORM COMMIT-TRANSACTION END-IF. BEGIN-TRANSACTION. DISPLAY "Beginning transaction..." MOVE 0 TO WS-ERROR-COUNT. TRANSACTION-OPERATION-1. MOVE "TRANS001" TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Transaction failed: Customer not found" END-READ. TRANSACTION-OPERATION-2. MOVE "TPROD001" TO PROD-ID READ PRODUCT-FILE KEY IS PROD-ID INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Transaction failed: Product not found" END-READ. TRANSACTION-OPERATION-3. *> Simulate order creation MOVE 3 TO WS-ORDER-KEY WRITE ORDER-RECORD INVALID KEY ADD 1 TO WS-ERROR-COUNT DISPLAY "Transaction failed: Order creation error" END-WRITE. ROLLBACK-TRANSACTION. DISPLAY "Rolling back transaction due to errors..." *> In real application, undo all changes. COMMIT-TRANSACTION. DISPLAY "Committing successful transaction...". COMPREHENSIVE-ERROR-ANALYSIS. DISPLAY "=== COMPREHENSIVE ERROR ANALYSIS ===" *> Analyze different types of invalid key errors PERFORM ANALYZE-FILE-STATUS-CODES PERFORM TEST-BOUNDARY-CONDITIONS PERFORM TEST-CONCURRENT-ACCESS. ANALYZE-FILE-STATUS-CODES. DISPLAY "Analyzing file status codes:" MOVE "ANALYZE1" TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY EVALUATE WS-CUST-STATUS WHEN "23" DISPLAY " Status 23: Record not found" WHEN "22" DISPLAY " Status 22: Duplicate key" WHEN "24" DISPLAY " Status 24: Boundary violation" WHEN OTHER DISPLAY " Other status: " WS-CUST-STATUS END-EVALUATE END-READ. TEST-BOUNDARY-CONDITIONS. DISPLAY "Testing boundary conditions:" *> Test with empty key MOVE SPACES TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY " Empty key handled correctly" END-READ *> Test with high values MOVE HIGH-VALUES TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY " High values key handled correctly" END-READ. TEST-CONCURRENT-ACCESS. DISPLAY "Testing concurrent access scenarios:" *> Simulate record locked by another process MOVE "LOCKED01" TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY IF WS-CUST-STATUS = "9D" DISPLAY " Record locked by another process" ELSE DISPLAY " Other concurrent access issue: " WS-CUST-STATUS END-IF END-READ.
123456789101112131415161701 WS-CUSTOMER-ID PIC X(8). 01 WS-FOUND-FLAG PIC X VALUE 'N'. 88 CUSTOMER-FOUND VALUE 'Y'. PROCEDURE DIVISION. MOVE "CUST0001" TO WS-CUSTOMER-ID MOVE WS-CUSTOMER-ID TO CUST-ID READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Customer not found: " WS-CUSTOMER-ID PERFORM CUSTOMER-NOT-FOUND-PROCESSING NOT INVALID KEY SET CUSTOMER-FOUND TO TRUE PERFORM PROCESS-CUSTOMER-RECORD END-READ.
123456789101112131415PROCEDURE DIVISION. *> Attempt to create new customer WRITE CUSTOMER-RECORD INVALID KEY IF WS-FILE-STATUS = "22" DISPLAY "Customer already exists: " CUST-ID PERFORM HANDLE-EXISTING-CUSTOMER ELSE DISPLAY "Write error: " WS-FILE-STATUS PERFORM HANDLE-WRITE-ERROR END-IF NOT INVALID KEY DISPLAY "Customer created successfully: " CUST-ID ADD 1 TO WS-CUSTOMERS-CREATED END-WRITE.
When should you use the INVALID KEY clause?
Answer: Use INVALID KEY with indexed and relative file operations (READ, WRITE, REWRITE, DELETE, START) to handle key-related errors like record not found, duplicate keys, or invalid key values.
How does INVALID KEY relate to file status codes?
Answer: INVALID KEY triggers when file operations fail (file status not "00"). You can check specific file status codes within the INVALID KEY clause to determine the exact error type (23=not found, 22=duplicate, etc.).
What are effective recovery patterns for INVALID KEY scenarios?
Answer: Effective patterns include alternative searches for not found records, update operations for duplicate keys, logging for audit trails, retry mechanisms for transient errors, and graceful degradation for continued processing.
12345678READ CUSTOMER-FILE KEY IS CUST-ID INVALID KEY DISPLAY "Customer not found: " CUST-ID PERFORM SEARCH-ALTERNATIVES NOT INVALID KEY PERFORM PROCESS-CUSTOMER END-READ
123456789WRITE CUSTOMER-RECORD INVALID KEY IF FILE-STATUS = "22" DISPLAY "Duplicate customer: " CUST-ID PERFORM UPDATE-EXISTING-CUSTOMER END-IF NOT INVALID KEY DISPLAY "Customer added: " CUST-ID END-WRITE