# Database Migrations

This project uses [drizzle-kit](https://orm.drizzle.team/kit-docs/overview) for database schema management and migrations.

## Overview

- **Schema definition:** `src/db/schema.ts` (drizzle-orm table definitions)
- **Migration output:** `drizzle/` directory (SQL files + meta journal)
- **Config:** `drizzle.config.ts`
- **Runtime migrator:** `src/db/ensure-schema.ts` (calls `drizzle-orm/better-sqlite3/migrator`)

## How It Works

On every server startup, `ensureSchema(db)` runs all pending migrations from the `drizzle/` folder. Drizzle tracks applied migrations in a `__drizzle_migrations` table so only new migrations are applied. This is safe to call repeatedly.

## Workflow

### Making schema changes

1. Edit `src/db/schema.ts` with your table/column changes
2. Generate a migration:
   ```bash
   npx drizzle-kit generate
   ```
3. Review the generated SQL in `drizzle/NNNN_*.sql`
4. Commit the migration file along with your schema change

### Applying migrations

Migrations are applied automatically on server startup. No manual step needed.

For tests, the same `ensureSchema()` function is called on in-memory SQLite databases in `src/db/repositories/drizzle/test-helpers.ts`.

### Checking migration status

```bash
# See what drizzle-kit would generate (dry run)
npx drizzle-kit generate --dry-run

# Open drizzle studio to inspect the database
npx drizzle-kit studio
```

## Rules

- **Never hand-write migration SQL.** Always use `drizzle-kit generate` from the schema.
- **Never use raw CREATE TABLE statements** for schema initialization. The migration system handles this.
- **Always commit migration files.** They are the source of truth for database evolution.
- **Migration files are immutable.** Once committed, never edit them. Make a new migration instead.
- **Test with `npx vitest run`** after generating migrations to verify they work with in-memory databases.
