Before dropping tables, save all existing lat/lon coordinates keyed by URN.
After reimport, merge cached coordinates with any newly geocoded ones so
schools that already have coordinates skip the postcodes.io API call.
This makes repeated reimports fast and avoids re-geocoding ~15k schools.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
On startup, the app now checks if the database schema version matches
the code. If there's a mismatch or no version exists, it automatically
runs a full data migration before starting.
- Add backend/version.py with SCHEMA_VERSION constant
- Add backend/migration.py with extracted migration logic
- Add SchemaVersion model to track DB version
- Add version check functions to database.py
- Update app.py lifespan to use check_and_migrate_if_needed()
- Simplify migrate_csv_to_db.py to use shared logic
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
