A VS Code extension that analyzes the impact of changing a field length in an IBM i physical file. It instantly shows every dependent object — logical files, indexes, triggers, SQL routines, and programs — that will need attention before and after an ALTER TABLE or file change.

Disclaimer: This extension is an independent tool and is not affiliated with or endorsed by IBM.

Features

Right-click integration — invoke directly from the IBM i Object Browser on any *FILE object
Command Palette support — run from anywhere with Ctrl+Shift+P
Field picker — select from a list of all columns in the file, showing current type and length
Quick Scan — SQL-based, returns in seconds: logical files, indexes, triggers, SQL procedures/functions
Deep Scan — additionally runs DSPPGMREF on the library to find every *PGM and *SRVPGM that compiles against the file
Visual report — styled webview panel with impact grouped by object type, certainty badges, and a full column structure table
Copy to clipboard — export the file structure table with one click

Prerequisites

Requirement	Detail
VS Code	1.80 or later
Code for IBM i	`halcyontechltd.code-for-ibmi` — must be installed and connected
IBM i	Any release with `QSYS2` SQL catalog access (IBM i 7.1+)

The extension uses the active IBM i connection managed by Code for IBM i. No separate connection setup is required.

Installation

From VSIX file

Open VS Code
Go to Extensions (Ctrl+Shift+X)
Click the ··· menu (top-right of the Extensions panel) → Install from VSIX…
Select field-change-impact-for-ibmi-1.0.2.vsix

Or via the terminal:

code --install-extension field-change-impact-for-ibmi-1.0.2.vsix

Usage

From the IBM i Object Browser (right-click)

Expand your library in the Object Browser panel (provided by Code for IBM i)
Right-click any *FILE object
Select Analyze Field Length Change Impact

The extension reads the library and file name from the selected item automatically.

From the Command Palette

Press Ctrl+Shift+P
Type Field Change Impact or Analyze Field Length
Select Field Change Impact: Analyze Field Length Change Impact
Enter the library name when prompted (e.g. MYLIB)
Enter the physical file name when prompted (e.g. CUSTMAST)

Step-by-step Walkthrough

Once a file is identified (either from the Object Browser or entered manually), the extension guides you through four quick steps:

Step 1 ── Pick the field being changed
          Shows all columns with current type and length

Step 2 ── Enter the new length
          Validates it is a positive integer different from the current length

Step 3 ── Choose scan depth
          Quick Scan  ─ SQL catalog only (seconds)
          Deep Scan   ─ SQL + DSPPGMREF cross-reference (slower, more complete)

Step 4 ── View the impact report
          Opens in a new editor tab

Understanding the Report

The report groups dependent objects into sections:

Section	Certainty	How it is found
Logical File	Definitive	`QSYS2.SYSTABLES` — `BASE_TABLE_NAME` match
SQL View	Definitive	`QSYS2.SYSTABLES` — view over the physical
Index / Access Path	Definitive	`QSYS2.SYSINDEXES`
Trigger	Definitive	`QSYS2.SYSTRIGGERS`
SQL Procedure / Function	Potential	`QSYS2.SYSROUTINES` in same library — verify manually
*Program (`PGM`)**	Definitive	`DSPPGMREF` output (Deep Scan only)
*Service Program (`SRVPGM`)**	Definitive	`DSPPGMREF` output (Deep Scan only)

Definitive means the dependency is confirmed by system catalog data.
Potential means the object is in the same library and may reference the file — manual verification is recommended.

Summary Cards

The top of the report shows:

Total Dependents — all objects found
Definitive — confirmed dependencies (green)
Potential — objects to verify (amber)
Object Types — number of distinct categories affected

Quick Scan vs Deep Scan

	Quick Scan	Deep Scan
Speed	Seconds	Minutes (depends on library size)
Logical files	Yes	Yes
Indexes	Yes	Yes
Triggers	Yes	Yes
SQL routines	Yes (potential)	Yes (potential)
PGM / SRVPGM	No	Yes (definitive)
IBM i command used	None — SQL only	`DSPPGMREF PGM(LIB/*ALL)`
When to use	Initial impact check	Before planning recompile schedule

The Deep Scan writes a temporary outfile to QTEMP during the run and deletes it when done.

Troubleshooting

"Code for IBM i (Code4i) extension is not installed"

Install the halcyontechltd.code-for-ibmi extension from the VS Code Marketplace and connect to an IBM i system.

"Not connected to IBM i"

Open the Code for IBM i panel and establish a connection before running the analysis.

"No columns found for LIB/FILE"

Confirm the file exists in the specified library
Confirm it is a physical file (*FILE with attribute PF)
Confirm your IBM i user has *USE authority to QSYS2.SYSCOLUMNS

Deep Scan fails or returns no programs

Your IBM i user needs authority to run DSPPGMREF and to create objects in QTEMP
Large libraries (thousands of programs) may take several minutes
If DSPPGMREF is not available on your IBM i release, use Quick Scan and review programs manually

Limitations

Only analyzes physical files (*FILE PF). Logical files and SQL views are shown as dependents, not as input sources.
SQL routine dependencies are listed as potential because QSYS2.SYSROUTINES does not expose the routine body for cross-referencing. Review them manually.
Programs compiled against a logical file (rather than directly against the physical) are only found if the logical file itself appears in the Deep Scan results.
Deep Scan scans the entire specified library. Cross-library program references are not covered.

Disclaimer

This extension is an independent tool and is not affiliated with or endorsed by IBM.

License

MIT — see LICENSE

Field Change Impact - for IBMi