Microsoft Access VCS Project Guide
Rules and gotchas for programmatically editing Access objects exported by VCS 4.x. Violations cause silent corruption or Error 2128 on import via LoadComponentFromText.
Reference Files
Read the relevant reference file before working on a specific object type:
| When working on... |
Read this reference |
Form .bas layout or form controls |
references/forms.md |
Report .bas layout, sections, or sorting/grouping |
references/reports.md |
| Images in forms or reports (add, replace, convert from OLE) |
references/images.md |
| Conditional formatting (forms or reports) |
references/conditional-formatting.md |
Queries (.bas + .sql) |
references/queries.md |
| Tables, relationships, or ODBC connections |
references/tables-and-relationships.md |
VBA modules (.bas) or code-behind (.cls) |
references/vba.md |
| Project config files (vcs-options, vcs-index, etc.) |
references/project-config.md |
| Macros, shared images, or import/export specs |
references/other-objects.md |
Project Overview
A VCS-exported Access project lives in <DatabaseName>.accdb.src/. The directory name must match the .accdb filename with .src appended.
File Pairing Rules
| Object Type |
Files |
Notes |
| Form |
.bas + optional .cls + optional .json |
.bas = layout, .cls = VBA code-behind (omitted if no code), .json = print settings |
| Report |
.bas + optional .cls + optional .json |
Same binary text format as forms, .cls = VBA code-behind (uncommon but valid), .json = print settings |
| Query |
.bas + .sql |
.bas = metadata/designer state, .sql = SQL text. Always paired |
| Module |
.bas |
Standard VBA module |
| Relationship |
.json |
Foreign key definition, join type, referential integrity |
| Linked Table |
.json |
Connection string, source table, attributes |
| Local Table |
.xml |
XSD schema defining columns, data types, indexes. For tables stored inside the .accdb |
| Macro |
.bas |
Access macro actions (not VBA). Simpler binary text format |
| Shared Image |
.json + image file |
.json = metadata (name, extension, hash), paired with actual image file (.png, .jpg, etc.) |
| Import/Export Spec |
.json |
Column definitions, delimiters, data types |
| Theme |
.thmx |
Office theme (binary OOXML archive — do not edit) |
When deleting an object, delete ALL its associated files plus its entry in vcs-index.json.
Encoding
All JSON configuration files and .sql files use UTF-8 with BOM (byte order mark EF BB BF). The BOM must be preserved when editing. Binary text .bas files (forms, reports, macros) also use UTF-8 with BOM. .bas, .cls, and tbldef/relation .json files additionally use CRLF line endings (enforced via .gitattributes).
Creating a new file from scratch: standard write tools (including Claude's Write tool, echo, cat <<EOF) silently produce UTF-8 without BOM and use LF endings — this will corrupt the import. To create a new VCS file, emit the bytes explicitly:
printf '\xEF\xBB\xBF{\r\n "Info": { ... }\r\n}\r\n' > path/to/new-file.json
Verify after writing: od -c -N 5 path/to/new-file.json should show 357 273 277 (the BOM) as the first three bytes, and the file should contain \r before each \n. Editing an existing file with Edit/Read preserves the original encoding — the BOM-stripping issue only applies to brand-new files created via Write.
Safe Deletion Checklist
Before deleting any Access object:
- Search for references in all
.cls, .bas, .sql files. Objects may be referenced by:
- VBA code (
DoCmd.OpenForm, DoCmd.OpenReport, DoCmd.OutputTo)
- Query SQL (
FROM tableName, subreport SourceObject)
- Form RecordSource properties
- DLookup expressions
- Check for name collisions. Objects with similar names may serve completely different purposes (e.g., an active report and a dead integration table that share a prefix).
- Delete all paired files (.bas + .sql, .bas + .cls + .json, etc.)
- Remove from config files: vcs-index.json, db-connection.json, hidden-attributes.json
- Renumber TabIndex values in any form/report section where a control was removed
- Test import in Access after changes
Common Pitfalls
- Commented-out code referencing kept objects: Leave commented VBA lines alone if they reference objects you're keeping.
- db-connection.json: Must contain only one connection entry matching the canonical ODBC connection string used by all linked tables and pass-through queries. Never introduce plaintext passwords or user-specific credentials.
1---2name: ms-access-vcs3description: Working with Microsoft Access databases exported via VCS (Version Control System for Access). Use when editing Access form definitions (.bas), report definitions, query files, VBA modules, linked table definitions, or VCS configuration files. Covers structural rules, common gotchas, and safe editing practices for the binary text format used by Access's LoadFromText/SaveAsText.4---56# Microsoft Access VCS Project Guide78Rules and gotchas for programmatically editing Access objects exported by VCS 4.x. Violations cause silent corruption or `Error 2128` on import via `LoadComponentFromText`.910## Reference Files1112Read the relevant reference file before working on a specific object type:1314| When working on... | Read this reference |15|---|---|16| Form `.bas` layout or form controls | `references/forms.md` |17| Report `.bas` layout, sections, or sorting/grouping | `references/reports.md` |18| Images in forms or reports (add, replace, convert from OLE) | `references/images.md` |19| Conditional formatting (forms or reports) | `references/conditional-formatting.md` |20| Queries (`.bas` + `.sql`) | `references/queries.md` |21| Tables, relationships, or ODBC connections | `references/tables-and-relationships.md` |22| VBA modules (`.bas`) or code-behind (`.cls`) | `references/vba.md` |23| Project config files (vcs-options, vcs-index, etc.) | `references/project-config.md` |24| Macros, shared images, or import/export specs | `references/other-objects.md` |2526## Project Overview2728A VCS-exported Access project lives in `<DatabaseName>.accdb.src/`. The directory name **must** match the `.accdb` filename with `.src` appended.2930### File Pairing Rules3132| Object Type | Files | Notes |33|-------------|-------|-------|34| Form | `.bas` + optional `.cls` + optional `.json` | `.bas` = layout, `.cls` = VBA code-behind (omitted if no code), `.json` = print settings |35| Report | `.bas` + optional `.cls` + optional `.json` | Same binary text format as forms, `.cls` = VBA code-behind (uncommon but valid), `.json` = print settings |36| Query | `.bas` + `.sql` | `.bas` = metadata/designer state, `.sql` = SQL text. Always paired |37| Module | `.bas` | Standard VBA module |38| Relationship | `.json` | Foreign key definition, join type, referential integrity |39| Linked Table | `.json` | Connection string, source table, attributes |40| Local Table | `.xml` | XSD schema defining columns, data types, indexes. For tables stored inside the .accdb |41| Macro | `.bas` | Access macro actions (not VBA). Simpler binary text format |42| Shared Image | `.json` + image file | `.json` = metadata (name, extension, hash), paired with actual image file (`.png`, `.jpg`, etc.) |43| Import/Export Spec | `.json` | Column definitions, delimiters, data types |44| Theme | `.thmx` | Office theme (binary OOXML archive — do not edit) |4546When deleting an object, delete ALL its associated files plus its entry in `vcs-index.json`.4748### Encoding4950All JSON configuration files and `.sql` files use **UTF-8 with BOM** (byte order mark `EF BB BF`). The BOM must be preserved when editing. Binary text `.bas` files (forms, reports, macros) also use UTF-8 with BOM. `.bas`, `.cls`, and tbldef/relation `.json` files additionally use **CRLF** line endings (enforced via `.gitattributes`).5152**Creating a new file from scratch:** standard write tools (including Claude's `Write` tool, `echo`, `cat <<EOF`) silently produce UTF-8 *without* BOM and use **LF** endings — this will corrupt the import. To create a new VCS file, emit the bytes explicitly:5354```bash55printf '\xEF\xBB\xBF{\r\n "Info": { ... }\r\n}\r\n' > path/to/new-file.json56```5758Verify after writing: `od -c -N 5 path/to/new-file.json` should show `357 273 277` (the BOM) as the first three bytes, and the file should contain `\r` before each `\n`. *Editing* an existing file with `Edit`/`Read` preserves the original encoding — the BOM-stripping issue only applies to brand-new files created via `Write`.5960## Safe Deletion Checklist6162Before deleting any Access object:63641. **Search for references** in all `.cls`, `.bas`, `.sql` files. Objects may be referenced by:65 - VBA code (`DoCmd.OpenForm`, `DoCmd.OpenReport`, `DoCmd.OutputTo`)66 - Query SQL (`FROM tableName`, subreport `SourceObject`)67 - Form RecordSource properties68 - DLookup expressions692. **Check for name collisions.** Objects with similar names may serve completely different purposes (e.g., an active report and a dead integration table that share a prefix).703. **Delete all paired files** (.bas + .sql, .bas + .cls + .json, etc.)714. **Remove from config files:** vcs-index.json, db-connection.json, hidden-attributes.json725. **Renumber TabIndex** values in any form/report section where a control was removed736. **Test import** in Access after changes7475## Common Pitfalls7677- **Commented-out code referencing kept objects:** Leave commented VBA lines alone if they reference objects you're keeping.78- **db-connection.json:** Must contain only one connection entry matching the canonical ODBC connection string used by all linked tables and pass-through queries. Never introduce plaintext passwords or user-specific credentials.
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