# Skill: Database Schema Change

Purpose: Safely plan and execute schema changes across Access, SQLite, SQL Server, or Postgres.

## Steps
1. Document the current schema (relevant tables/fields) in the spec.
2. Write the exact DDL/change statements for the target engine, following `.devfoundry/rules/database-sql.md`.
3. Identify all known dependent queries, views, or reports (check `.devfoundry/references/data-dictionary.md`).
4. Provide a rollback statement or backup step. For Access `.mdb`/`.accdb` files this is mandatory: before any structural change, copy the file with a timestamped suffix (e.g. `copy "<path>.accdb" "<path>_backup_<YYYYMMDD-HHMM>.accdb"` from a command prompt, or `FileCopy` in VBA/VB6) and confirm the copy exists and opens before proceeding. Record the exact backup command and path used in the spec's Implementation Plan.
5. Test the change in a non-production copy of the database before applying it live.