REFORMAT Statement

What REFORMAT Does

When you join two files with JOINKEYS, each matched pair (or unpaired record in an outer join) becomes one output record. REFORMAT defines the layout of that output record: which fields from the first file (F1) and which from the second file (F2) are placed in the output, and in what order. So REFORMAT does not filter or sort—it only specifies how to build the joined record from the two sides.

REFORMAT FIELDS= Syntax

REFORMAT FIELDS=(item1,item2,...). Each item is either:

• F1:position,length — Copy length bytes from the first join file starting at position. The first file is the one in the first JOINKEYS statement (e.g. F1=JOIN1).
• F2:position,length — Copy length bytes from the second join file starting at position. The second file is the one in the second JOINKEYS statement.

Positions are 1-based. The output record length is the sum of all the lengths. Example: FIELDS=(F1:1,80,F2:11,70) → 80 + 70 = 150 bytes: full 80-byte record from F1, then bytes 11–80 from F2 (70 bytes).

Example with JOINKEYS

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  JOINKEYS F1=MASTER,FIELDS=(1,10,CH,A)
  JOINKEYS F2=TRANS,FIELDS=(1,10,CH,A)
  REFORMAT FIELDS=(F1:1,80,F2:11,50)
  SORT FIELDS=COPY

Joined output: 80 bytes from MASTER (positions 1–80), then 50 bytes from TRANS (positions 11–60). Total 130 bytes per joined record. The join key (bytes 1–10) is in both files; REFORMAT includes the full master record and part of the transaction record.

REFORMAT vs INREC/OUTREC

INREC and OUTREC reformat a single record stream (one input file). REFORMAT builds a record from two files that have been paired by JOINKEYS. So you use REFORMAT only in join applications; for non-join steps you use INREC (before sort) or OUTREC (after sort).

Explain It Like I'm Five

When you join two stacks of cards, you get one new card per match. REFORMAT is the rule for what to write on that new card: "Take this part from the first card and that part from the second card, and put them in this order." So REFORMAT doesn't decide who matches—JOINKEYS does—it only decides how the combined card looks.

Exercises

1. Write REFORMAT FIELDS= to output: first 30 bytes of F1, then bytes 5–20 of F2. What is the output length?
2. Why is REFORMAT required when using JOINKEYS?