Easytrieve Virtual Fields

Virtual Fields vs FILE Fields

FILE statement fields map to record positions on disk. Virtual fields map to working storage in the address space. READ loads FILE fields from the dataset. Virtual fields start at VALUE or default zeros and blanks until JOB logic assigns them. You can PRINT both on one report line—GROSS from file and NET-PAY from working storage—but only GROSS travels in from the input buffer on READ.

W Virtual Fields and Report Spooling

Broadcom documents that W fields copy to report work files when referenced in REPORT subactivities and PRINT executes. Formatting and printing happen later—sometimes after SORT on the work file. The W value on the work file is whatever it was at PRINT time. If you increment WS-COUNT after PRINT, the report still shows the old spooled value. If you accumulate a running total in W during the file and then SORT, the work file carries per-record W snapshots that may not equal the final accumulated value.

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DEFINE WS-RANK W 3 N
 
JOB INPUT PERSNL
  WS-RANK = WS-RANK + 1
  PRINT PERSNL-RPT
  REPORT PERSNL-RPT
    TITLE 'PERSONNEL'
    LINE WS-RANK NAME GROSS
  END-REPORT

WS-RANK is virtual— not on PERSNL file. Each printed line spools WS-RANK at PRINT. SORT on the report reorders spooled ranks with names—behavior you must predict when designing ranking reports.

S Static Virtual Fields

S fields stay in static working storage. They are not copied to report work files on each PRINT. References in REPORT format use current S values when lines print—better for grand totals, company name constants, and BAR-GRAPH built in BEFORE-BREAK PROCs. Broadcom recommends S unless you understand W spooling implications.

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DEFINE GRAND-TOT S 9 P 2
DEFINE BAR-GRAPH S 40 A
 
JOB INPUT PERSNL
  GRAND-TOT = GRAND-TOT + GROSS
  PRINT SALARY-RPT

Virtual Derived Fields

Most virtual fields are derived—computed from FILE or other virtual fields. NET-PAY W 7 P 2 virtual storage holds GROSS minus deductions. The derivation happens in assignment; the virtual aspect is storage class W. Combine derived-fields page patterns with virtual spooling rules here.

FILE VIRTUAL (VFM) — Not a Virtual Field

FILE SORTWRK FB(150 1800) VIRTUAL declares a temporary file managed by Virtual File Manager. VFM allocates memory and spills to disk when needed. SORT work files often use VIRTUAL so JCL does not allocate SORTWRK DD. RETAIN keeps VFM data between steps in multi-step programs. Do not confuse this FILE parameter with virtual W fields.

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FILE SORTWRK FB(150 1800) VIRTUAL
FILE PERSNL  FB(150 1800)
 
SORT PERSNL USING EMPL#
  OUT SORTWRK
END-SORT

Qualifying Virtual Fields with WORK

When the same name exists on FILE and in working storage, qualify with WORK:FLD1 versus FILEA:FLD1. Virtual fields without name collision need no qualifier. Ambiguous references compile to wrong buffer—use WORK: prefix in mixed layouts.

Virtual Fields in Online SCREEN Activities

Screen maps display virtual W fields for prompts, echo switches, and computed messages. RESET on W virtual fields restores VALUE when SCREEN activity restarts. FILE fields on screen maps still map to transaction buffers—virtual fields hold UI state.

Virtual Fields and SORT

When SORT sequences report work files containing spooled W virtual fields, those fields sort as ordinary columns on the work record. Accumulators in W that should represent running totals across the entire input file may sort incorrectly if you expected one final total per department. Use S for department totals that format after sort, or restructure JOB into two passes.

Choosing W or S for Virtual Fields

Common Mistakes

1. Confusing FILE VIRTUAL with virtual W fields.
2. Accumulating file-wide total in W then SORTing report work file.
3. PRINT before assigning virtual derived field.
4. Expecting RESET during report formatting pass.
5. Same field name on FILE and W without WORK: qualifier.
6. Putting virtual field on FILE layout when not on physical record.

Explain It Like I'm Five

File fields are names written on each card from the mail pile. Virtual fields are sticky notes you keep on your desk while reading the pile—they are not printed on the cards. When you photocopy a card for a report, W virtual notes get taped on the copy at photocopy time. S virtual notes stay on your desk until the report is actually stapled—you read the latest note then. VIRTUAL on FILE is a temporary cardboard box for sorted cards—not a sticky note at all.

Exercises

1. Define W virtual rank field; PRINT each record; explain spooled value.
2. Define S grand total; add GROSS each record; use on final LINE.
3. Write FILE SORTWRK VIRTUAL for a SORT step without JCL DD.
4. Qualify WORK:COUNT when COUNT exists on FILE and in storage.
5. Diagram timing: assignment, PRINT, SORT, format for W field.