Mini Project: Item Master Lookup Program

What We Are Building

A second, independent inquiry program, structurally similar to the Customer Inquiry Program mini project, but introducing a brand new file: ITEMPF, an item master. This project is a chance to apply the same pattern again on your own, with a new business object.

Business Scenario

Imagine a warehouse worker checking an item's description and current price before pulling stock for an order. Rather than digging through a paper catalog, they type the item number into a simple screen and see the answer immediately, the same everyday need as the customer inquiry project, applied to a different kind of data.

Concepts Used

The same core pattern as the Customer Inquiry Program mini project: display files, dcl-f and exfmt, CHAIN and %FOUND, and function keys. This project is deliberately similar in shape, so the focus is on applying the pattern to new fields and a new file rather than learning new mechanics.

Files and Programs Involved

• ITEMPF, a new keyed physical file, with fields for ITEMNBR (item number, the key), ITEMDESC (description), and ITEMPRICE (current price).
• ITEMDSPF, a new display file with one record format, ITEMFMT, containing an input field for item number and output fields for description and price.
• ITEMINQR, the RPGLE program tying ITEMDSPF and ITEMPF together.

Step-by-Step Build Outline

1. Define ITEMPF as a keyed physical file, ITEMNBR as its key, exactly as covered in the Keyed Physical Files lesson.
2. Design ITEMDSPF's ITEMFMT record format: an input field for item number, output fields for description and price, and an F3 exit key.
3. Declare both files in an RPGLE program, ITEMINQR, with dcl-f.
4. Loop calling exfmt ITEMFMT, reading the item number entered.
5. Use CHAIN against ITEMPF, check %FOUND, and set an error message indicator if nothing was found.
6. Check the F3 indicator each pass to exit cleanly.

Example Code

dcl-f ITEMDSPF workstn;
dcl-f ITEMPF disk keyed;

dcl-s exitRequested ind;

dow not exitRequested;
  exfmt ITEMFMT;

  if *in03;
    exitRequested = *on;
  else;
    chain ITEMNBR ITEMPF;
    if %found(ITEMPF);
      *in50 = *off;
    else;
      *in50 = *on;
    endif;
  endif;
enddo;

*inlr = *on;

Notice this is structurally the same shape as the Customer Inquiry Program mini project's code, with ITEMNBR and ITEMPF in place of CUSTNBR and CUSTMAST. Recognizing this repeatable shape is exactly the point of building a second, similar project.

How to Test It

Test with an item number that exists, confirming description and price display correctly; an item number that does not exist, confirming the error message appears; and pressing F3 immediately to confirm a clean exit, the same three cases used for the customer inquiry project.

Common Mistakes

• Copying the pattern but forgetting to change every CUSTNBR/CUSTMAST reference to ITEMNBR/ITEMPF, leaving a mismatched, broken program.
• Defining ITEMPF without a key, which would prevent CHAIN from working at all.
• Reusing the same message indicator number as another program without checking whether that matters for this specific program's own DDS.

Debugging Checklist

If item descriptions or prices show as blank or stale, follow the same checklist as the Customer Inquiry Program mini project: check %FOUND's actual value with EVAL right after the CHAIN, and confirm ITEMNBR holds the exact value expected at that point.

Possible Extensions

A natural extension is adding a low-stock or discontinued flag to ITEMPF, displayed as a highlighted message on ITEMDSPF when set, using DSPATR, covered in the Basic Display File DDS Keywords lesson.

Quick Recap

• ITEMINQR applies the exact same inquiry pattern as the Customer Inquiry Program mini project, to a new file and new fields.
• Recognizing and reusing a repeatable pattern, rather than learning something new each time, is a genuinely valuable developer skill.
• The same three test cases, found, not found, and immediate exit, apply here as well.

Try Asking the AI Tutor

Use the AI Tutor to practice extending or troubleshooting this project. For example, try asking:

• "What would change in this program if ITEMPF needed to be looked up by a description search instead of an exact item number?"
• "How similar is this program's structure to CUSTINQR from the Customer Inquiry Program project, and why does that similarity matter?"