The American Programmer

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9. The Sequential File, Batch Update Program FILEUPD1. It reads two files, a Master File and a Transaction File. It matches records by comparing a significant field, such as account number. A code on the Transaction Record tells it whether to Add, Change or Delete Master File records. An output file is produced that contains the added, changed and unchanged Master File records. Credit card file maintenance: approved customers now can carry plastic money as they are added to the huge cardholder file (Add transactions.) Some souls will have their wallets/pocketbooks lightened a bit, since they are being dropped from the file and have to turn in their credit cards (Delete transactions.) Those who have kept within their credit limit and have paid on time will see their credit limit raised to 3 times the size of the national debt of Mauritania! (Change transactions.) It’s one program that processes Adds, Deletes and Changes. It is usually done in Batch mode (not done on a terminal while someone waits, and waits....) Batch mode in the IBM mainframe world means that the job was submitted through JCL and runs when it runs. The results will be ready by morning (unless the programmer forgot something critical in the program...) Most batch file update programs are designed to use transaction codes on the transaction file. If a transaction file does not come with transaction codes, I consider that to be a design flaw, because it eliminates the logic checking that is possible with transaction codes: “If this is a match, what am I doing with an Add transaction?” All batch file update programs of this type assume that both the transaction file and the old, input master file are sorted in the same manner, on the same field or fields. If the files are not sorted this way, the program won’t work! The program reads the two input files: the transaction file and the old master file. It compares the key fields (sometimes called control fields) of the two files. The comparison can come out one of three ways: The transaction key equals the master key. In this case the program will apply the transaction to the master. This may be a change transaction or a delete transaction. It may not be an add transaction. The transaction key is greater than the master key. The program will write out the master record - there are no more transactions that apply to this master record. The transaction key is less than the master key. The transaction record did not find a corresponding master master record. This should happen with an add transaction. The model program is a real Marvel. It can handle multiple transactions for the same key. It can even handle an Add, followed by a Change, then a Delete all for the same key. This will work only if the transaction file is sorted by the key, and within the key, sorted by the transaction code. Luckily Add sorts before Change which sorts before Delete. I give you this model program for many reasons. First, because it works. This is not a trivial thing! This type of program can be a real bear. It can consume many hours before it does everything correctly. Second, because it is easier to rip code out of this program than to put it in. If you have a transaction file without Delete transactions, tear out the code for deleting. (If I were you, I’d leave it in, but commented out. Users can change their minds...) Third, because you don’t have to rip things out if you don’t need them. They will simply sit there in the program and never do anything. For example, if you never have multiple transactions for the same key, the program will still work perfectly, although there will be parts of the program that acquire cobwebs. Here is the program FILEUPD1: 000200 IDENTIFICATION DIVISION. 000300* File update. Works fine. Don't mess with it. 000400* this is a good way to do it. Use this as a model. 000500* transaction codes used. Multiple trans allowed for same account 000600 PROGRAM-ID. FILEUPD1. 000700 ENVIRONMENT DIVISION. 000800 CONFIGURATION SECTION. 000900 INPUT-OUTPUT SECTION. 001000 FILE-CONTROL. 001100 SELECT TRANS-FILE ASSIGN TRANSFIL. 001500 SELECT OLD-MASTER ASSIGN OLDMAST. 001900 SELECT NEW-MASTER ASSIGN NEWMAST. 002400 DATA DIVISION. 002500 FILE SECTION. 002600* 002700 FD TRANS-FILE 002800 RECORDING MODE IS F 003100 RECORD CONTAINS 80 CHARACTERS. 003200 01 TRANS-RECORD. 003300 05 TR-ACCT-NO PIC X(5). 003400 05 FILLER PIC X(5). 003500 05 TR-AMOUNT PIC 9(5). 003600 05 FILLER PIC X(5). 003700 05 TR-CUST-NAME PIC X(10). 003800 05 TR-TRANS-CODE PIC X(1). 003900 88 ADD-TRANS VALUE 'A'. 004000 88 CHANGE-TRANS VALUE 'C'. 004100 88 DELETE-TRANS VALUE 'D'. 004200 05 FILLER PIC X(44). 004300* 004400 FD OLD-MASTER 004500 RECORDING MODE IS F 004800 RECORD CONTAINS 80 CHARACTERS. 004900* 005000 01 OLD-MASTER-RECORD. 005100 05 OM-ACCT-NO PIC X(05). 005200 05 FILLER PIC X(05). 005300 05 OM-AMOUNT PIC 9(05). 005400 05 FILLER PIC X(05). 005500 05 OM-CUST-NAME PIC X(10). 005600 05 FILLER PIC X(50). 005700* 005800 FD NEW-MASTER 005900 RECORDING MODE IS F 006200 RECORD CONTAINS 80 CHARACTERS. 006300* 006400 01 NEW-MASTER-RECORD. 006500 05 NM-ACCT-NO PIC X(05). 006600 05 FILLER PIC X(05). 006700 05 NM-AMOUNT PIC 9(05). 006800 05 FILLER PIC X(05). 006900 05 NM-CUST-NAME PIC X(10). 007000 05 FILLER PIC X(50). 007100* 007200 WORKING-STORAGE SECTION. 007300 01 SWITCHES. 007400 05 MASTER-EOF PIC X VALUE 'N'. 007700* 007800 05 TRANS-EOF PIC X VALUE 'N'. 008100* 008200 05 SW-FINISHED-WITH-DATA PIC X VALUE 'N'. 008300 88 FINISHED-WITH-DATA VALUE 'Y'. 008400 88 NOT-FINISHED-WITH-DATA VALUE 'N'. 008500* 008600 05 SW-FIRST-TIME PIC X VALUE 'Y'. 008700 88 IT-IS-FIRST-TIME VALUE 'Y'. 008800* 008900 05 SW-VALID-DELETE PIC X VALUE 'N'. 009000 88 VALID-DELETE VALUE 'Y'. 009100* 009200 05 SW-VALID-ADD PIC X VALUE 'N'. 009300 88 VALID-ADD VALUE 'Y'. 009400* 009500 01 NEW-MASTER-WORK-AREA. 009600 05 WORK-NM-ACCT-NO PIC X(05). 009700 05 FILLER PIC X(05). 009800 05 WORK-NM-AMOUNT PIC 9(05). 009900 05 FILLER PIC X(05). 010000 05 WORK-NM-CUST-NAME PIC X(10). 010100 05 FILLER PIC X(50). 010200* 010300 PROCEDURE DIVISION. 010400* 010500 PERFORM INITIALIZATION 010600 PERFORM PROCESS-BOTH-FILES 010700 UNTIL MASTER-EOF = 'Y' 010800 AND TRANS-EOF = 'Y' 010900 IF FINISHED-WITH-DATA 011000 THEN 011100 PERFORM WRITE-NEW-MASTER 011200 END-IF 011300 PERFORM TERMINATION 011400 GOBACK. 011500* 011600 INITIALIZATION. 011700 OPEN INPUT TRANS-FILE 011800 OLD-MASTER 011900 OPEN OUTPUT NEW-MASTER 012000 MOVE SPACES TO NEW-MASTER-WORK-AREA 012100 MOVE 'N' TO MASTER-EOF 012200 MOVE 'N' TO TRANS-EOF 012300 MOVE 'N' TO SW-FINISHED-WITH-DATA 012400 MOVE 'Y' TO SW-FIRST-TIME 012500 MOVE 'N' TO SW-VALID-DELETE 012600 MOVE 'N' TO SW-VALID-ADD 012700 PERFORM GET-NEW-MASTER-DATA. 012800* 012900 PROCESS-BOTH-FILES. 013000 PERFORM WRITE-NEW-MASTER 013100 PERFORM GET-NEW-MASTER-DATA. 013200* 013300 WRITE-NEW-MASTER. 013400* MOVE FIELDS OF WORK AREA MASTER TO NEW MASTER RECORD 013500 MOVE SPACES TO NEW-MASTER-RECORD 013600 MOVE WORK-NM-ACCT-NO TO NM-ACCT-NO 013700 MOVE WORK-NM-AMOUNT TO NM-AMOUNT 013800 WRITE NEW-MASTER-RECORD. 013900* 014000 GET-NEW-MASTER-DATA. 014100 MOVE 'N' TO SW-FINISHED-WITH-DATA 014200 IF IT-IS-FIRST-TIME 014300 THEN 014400 PERFORM READ-TRANS 014500 PERFORM READ-MASTER 014600 MOVE 'N' TO SW-FIRST-TIME 014700 END-IF 014800 PERFORM COMPARE-ACCT-NO 014900 UNTIL FINISHED-WITH-DATA 015000 OR (MASTER-EOF = 'Y' 015100 AND TRANS-EOF = 'Y'). 015200* 015300 COMPARE-ACCT-NO. 015400 MOVE 'N' TO SW-VALID-DELETE 015500 MOVE 'N' TO SW-VALID-ADD 015600 IF MASTER-EOF IS NOT EQUAL TO 'Y' 015700 AND TRANS-EOF IS NOT EQUAL TO 'Y' 015800 THEN 015900 PERFORM MORE-RECORDS-IN-BOTH 016000 ELSE 016100 PERFORM ONE-FILE-IS-AT-END 016200 END-IF. 016300* 016400 MORE-RECORDS-IN-BOTH. 016500 IF TR-ACCT-NO IS EQUAL TO OM-ACCT-NO 016600 THEN 016700 PERFORM TR-EQUAL-OM 016800 ELSE 016900 IF TR-ACCT-NO IS GREATER THAN OM-ACCT-NO 017000 THEN 017100 PERFORM TR-GREATER-THAN-OM 017200 ELSE 017300 IF TR-ACCT-NO IS LESS THAN OM-ACCT-NO 017400 THEN 017500 PERFORM TR-LESS-THAN-OM 017600 END-IF. 017700* 017800 ONE-FILE-IS-AT-END. 017900 IF MASTER-EOF IS EQUAL TO 'Y' 018000 THEN 018100 PERFORM ADD-THIS-TRANS-IF-POSSIBLE 018200 IF VALID-ADD 018300 THEN 018400 MOVE 'Y' TO SW-FINISHED-WITH-DATA 018500 PERFORM READ-TRANS 018600 ELSE 018700 PERFORM READ-TRANS 018800 END-IF 018900 ELSE 019000* THERE ARE MORE MSTR RECORDS 019100 PERFORM JUST-MOVE-OM-TO-WORK 019200 MOVE 'Y' TO SW-FINISHED-WITH-DATA 019300 PERFORM READ-MASTER 019400 END-IF. 019500* 019600 TR-EQUAL-OM. 019700 PERFORM APPLY-TRANSACTION 019800 IF VALID-DELETE 019900 THEN 020000 PERFORM READ-MASTER 020100 PERFORM READ-TRANS 020200 ELSE 020300 PERFORM READ-TRANS 020400 END-IF. 020500* 020600 APPLY-TRANSACTION. 020700 IF CHANGE-TRANS 020800 THEN 020900 PERFORM PROCESS-CHANGE-TRANS 021000 ELSE 021100 IF DELETE-TRANS 021200 THEN 021300 MOVE 'Y' TO SW-VALID-DELETE 021400 ELSE 021500 IF ADD-TRANS 021600 THEN 021700 DISPLAY 'ALREADY ON FILE, CANNOT ADD THIS TRANSACTION' 021710 DISPLAY TRANS-RECORD 021720 DISPLAY SPACES 021800 END-IF. 021900* 022000 TR-LESS-THAN-OM. 022100 PERFORM ADD-THIS-TRANS-IF-POSSIBLE 022200 IF VALID-ADD 022300 THEN 022400 MOVE 'Y' TO SW-FINISHED-WITH-DATA 022500 PERFORM READ-TRANS 022600 ELSE 022700 PERFORM READ-TRANS 022800 END-IF. 022900* 023000 ADD-THIS-TRANS-IF-POSSIBLE. 023100 IF ADD-TRANS 023200 THEN 023300 MOVE TR-ACCT-NO TO WORK-NM-ACCT-NO 023400 MOVE TR-AMOUNT TO WORK-NM-AMOUNT 023500 MOVE TR-CUST-NAME TO WORK-NM-CUST-NAME 023600 MOVE 'Y' TO SW-VALID-ADD 023700 ELSE 023800 DISPLAY 'NO MATCH, CANNOT CHANGE/DELETE' 023810 DISPLAY TRANS-RECORD 023820 DISPLAY SPACES 023900 END-IF. 024000* 024100 TR-GREATER-THAN-OM. 024200 PERFORM JUST-MOVE-OM-TO-WORK 024300 MOVE 'Y' TO SW-FINISHED-WITH-DATA 024400 PERFORM READ-MASTER. 024500* 024600 JUST-MOVE-OM-TO-WORK. 024700 MOVE OM-ACCT-NO TO WORK-NM-ACCT-NO 024800 MOVE OM-AMOUNT TO WORK-NM-AMOUNT 024900 MOVE OM-CUST-NAME TO WORK-NM-CUST-NAME. 025000* 025100 PROCESS-CHANGE-TRANS. 025200 IF TR-CUST-NAME IS NOT EQUAL TO SPACES 025300 THEN 025400 MOVE TR-CUST-NAME TO OM-CUST-NAME 025500 END-IF 025600 ADD TR-AMOUNT TO OM-AMOUNT. 025700 READ-MASTER. 025800 READ OLD-MASTER 025900 AT END MOVE 'Y' TO MASTER-EOF 026000 END-READ. 026200 READ-TRANS. 026300 READ TRANS-FILE 026400 AT END MOVE 'Y' TO TRANS-EOF 026500 END-READ. 026700 TERMINATION. 026800 CLOSE TRANS-FILE 026900 OLD-MASTER 027000 NEW-MASTER. Here is the input transaction data file TRANSFIL: (the next two lines are a column ruler) 1 2 3 4 5 6 123456789.123456789.123456789.123456789.123456789.123456789.12345678 ACCT0 00100 GRUMPY CHANGE TRANSFIL ACCT1 00100 SNEAZZY ADD TRANSFIL ACCT1 00100 RUDOLPH CHANGE TRANSFIL ACCT1 00100 DELETE TRANSFIL ACCT2 00100 BLITZEN CHANGE TRANSFIL ACCT4 00100 THUMPER ADD TRANSFIL ACCT5 00100 DELETE TRANSFIL ACCT7 00100 MR ED ADD TRANSFIL ACCT8 00100 DONNER CHANGE TRANSFIL ACCT8 00100 WIMPY CHANGE TRANSFIL ACCT9 00100 TOTO CHANGE TRANSFIL Here is the old master data file OLDMAST: (the next two lines are a column ruler) 1 2 3 4 5 6 123456789.123456789.123456789.123456789.123456789.123456789.12345678 ACCT0 00010 LOU OLDMAST ACCT1 00010 MOE OLDMAST ACCT2 00010 CURLY OLDMAST ACCT3 00010 HAPPY OLDMAST ACCT5 00010 LAUREL OLDMAST ACCT6 00010 HARDY OLDMAST ACCT8 00010 DUMBO OLDMAST ACCT9 00010 GEORGE OLDMAST Here is sample JCL: //STEP1 EXEC PGM=FILEUPD1 //STEPLIB DD DSN=your.executable.program.library.goes.here,DISP=SHR //*OF COURSE, THE NEXT LIBRARY NAME MAY BE DIFFERENT AT YOUR COMPANY //TRANSFIL DD DSN=userid.COBBOOK.DATA(TRANSFIL),DISP=SHR //OLDMAST DD DSN=userid.COBBOOK.DATA(OLDMAST),DISP=SHR //NEWMAST DD SYSOUT=* //SYSOUT DD SYSOUT=* //SYSUDUMP DD SYSOUT=*

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