Easytrieve Multiple Files Processing

FILE Declarations for Each Dataset

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FILE TRANS    SEQUENTIAL FB(80 800)
TXN-EMP-NO  1  9 N
TXN-AMT    10  5 P 2
 
FILE EMPMAST  INDEXED UPDATE FB(200 2000)
EMP-NO      1  9 N
EMP-NAME   10 30 A
EMP-DEPT   40  3 A
 
FILE ERRFILE  SEQUENTIAL FB(80 800)
ERR-REC     1 80 A
 
FILE RPTOUT   SEQUENTIAL FB(120 1200)
OUT-LINE    1 120 A

Four unique file-names: TRANS drive file, EMPMAST KSDS master, ERRFILE sequential exceptions, RPTOUT successful output. Each needs a JCL DD with matching name (unless SYSNAME maps externally). Field layouts are independent per FILE. UPDATE on EMPMAST if the job rewrites master balances; omit UPDATE on read-only inquiry. PRINTER SYSPRINT is separate from these user files.

Primary JOB INPUT Pattern

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JOB INPUT TRANS
  MOVE TXN-EMP-NO TO EMP-NO
  READ EMPMAST
  IF EMPMAST-PRESENCE
     ADD TXN-AMT TO EMP-GROSS
     WRITE EMPMAST
     MOVE DETAIL-LINE TO OUT-LINE
     PUT RPTOUT
  ELSE
     MOVE ERROR-LINE TO ERR-REC
     PUT ERRFILE
  END-IF

TRANS is automatic input—Easytrieve GETs each transaction without explicit GET in source. Each iteration READs EMPMAST by key in EMP-NO moved from TXN-EMP-NO. Success path WRITEs master and PUTs RPTOUT; failure PUTs ERRFILE. Three files touched per row besides TRANS. You cannot code GET TRANS inside this loop. Secondary READ does not advance TRANS—only automatic input does.

Primary Versus Secondary Roles

JOB INPUT NULL and Controlled Multi-GET

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FILE FILEA SEQUENTIAL
FILE FILEB SEQUENTIAL
 
JOB INPUT NULL NAME MERGE
 
MERGE. PROC
  GET FILEA
  IF EOF FILEA
     STOP
  END-IF
  GET FILEB
  IF EOF FILEB
     STOP
  END-IF
  * compare keys and process match logic
END-PROC

When neither file should be automatic input—balanced merge, interleaved read, or programmer-controlled pacing—use JOB INPUT NULL and GET both files inside a procedure. Test EOF on each GET independently. Match-merge requires comparing key fields from both buffers before advancing the lagging file. This pattern is advanced for beginners but essential when two sequential ESDS files must be walked together without SORT first.

Mixing Organizations

ESDS TRANS plus INDEXED EMPMAST is the classic pair. ESDS plus RRDS slot table plus KSDS master appears in rating applications. Each organization uses correct FILE type: SEQUENTIAL, INDEXED, RELATIVE. JCL DD must point at matching catalog object. Do not READ keyed on ESDS; use INDEXED FILE for master. Sequential browse on multiple ESDS files means one JOB INPUT and secondary GET on the other with JOB INPUT NULL, or two-pass JOB with VIRTUAL intermediate.

TABLE SEARCH as Second Source

FILE DEPT-TABLE TABLE INSTREAM or external max-entries loads department names once. JOB INPUT TRANS uses SEARCH DEPT-TABLE instead of disk READ on a second master—reduces I/O when reference data is small. TABLE is still a FILE declaration but not sequential GET per row. Combine TABLE with INDEXED when static codes are in TABLE and volatile balances are on KSDS.

FILE DEFER and Open Order

DEFER on EMPMAST delays open until first READ—saves open cost when early transactions might exit on header validation before any lookup. DEFER on SQL files pairs with SELECT in START procedure. Default opens all non-DEFER files at activity start. Multi-file jobs with many DDs may hit open failures if one DD is missing—DEFER limits failure to first use, easing debugging.

Output Files and Automatic JOB Output

Besides explicit PUT RPTOUT, REPORT activities may target PRINTER files. Only one automatic output pattern per activity type applies—consult JOB and REPORT chapters. Multiple PUT files are fine in one JOB loop. Ensure SPACE and DISP on each output DD in JCL. ERRFILE and RPTOUT may both be GDG (+1) with different bases.

Multi-Activity Handoff

Activity one JOB INPUT TRANS PUT to SORTWRK VIRTUAL RETAIN. Activity two JOB SORT or JOB INPUT SORTWRK REPORT. CLOSE between activities on non-RETAIN files. RETAIN virtual work connects phases without cataloged temporaries. Production jobs separate compile/link/exec steps—not activities—but within one Easytrieve program, activities sequence file lifecycle.

CICS and Online Multi-File

Screen programs GET master files in BEFORE-SCREEN while SCREEN activity handles terminal I/O—another multi-file shape. Batch rules on automatic JOB INPUT do not apply; screen procedures use GET and READ with CICS-specific HOLD guidance. Keep batch multi-file tutorials separate from online WHEN learning paths.

Common Multi-File Mistakes

• GET on automatic JOB INPUT file.
• Two JOB INPUT files in one activity.
• READ master without moving key from primary buffer.
• Same file-name twice in FILE statements.
• EOF tested on primary only while secondary GET runs past end.
• INDEXED master declared SEQUENTIAL.

Testing Multi-File Programs

1. Run with empty TRANS—verify zero PUTs, clean EOF.
2. One txn with bad key—ERRFILE receives row, RPTOUT does not.
3. One txn with good key—master updates and RPTOUT PUT.
4. SYSPRINT record counts per file when DISPLAY counters coded.
5. Remove one DD—confirm DEFER delays ABEND until first use if applicable.

Explain It Like I'm Five

Multiple files are several boxes of cards. One box is the line you must deal with one card at a time—that is JOB INPUT. When you pick a card from the line box, you look up the same number in a big catalog box (READ on master). You put answer cards in the good pile (PUT output) or the mistake pile (ERRFILE). You cannot have two line boxes both moving automatically—you hold one line and manually pull from the other when you use JOB INPUT NULL.

Exercises

1. Declare TRANS, INDEXED MASTER, OUT, ERR; write JOB INPUT lookup loop.
2. Sketch JOB INPUT NULL merge pseudocode for two sequential files.
3. Add TABLE SEARCH replacing small master READ.
4. List JCL DD names required for four FILE declarations.
5. Document EOF tests needed for primary and secondary in NULL job.