4656627a59
Snapshots were stale since migration 0008. Generated a schema-derived snapshot at 0032 so drizzle-kit generate works again (zero diff on current schema.ts). Also fixed migration 0032 to use statement-breakpoint separator required by better-sqlite3. - Added 0032_snapshot.json derived from current schema.ts - Fixed 0032 SQL to use --> statement-breakpoint between statements - Updated CLAUDE.md and database-migrations.md with correct workflow
58 lines
3.0 KiB
Markdown
58 lines
3.0 KiB
Markdown
# Database Migrations
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This project uses [drizzle-kit](https://orm.drizzle.team/kit-docs/overview) for database schema management and migrations.
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## Overview
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- **Schema definition:** `apps/server/db/schema.ts` (drizzle-orm table definitions)
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- **Migration output:** `apps/server/drizzle/` directory (SQL files + `meta/_journal.json` + `meta/NNNN_snapshot.json`)
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- **Config:** `drizzle.config.ts`
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- **Runtime migrator:** `apps/server/db/ensure-schema.ts` (calls `drizzle-orm/better-sqlite3/migrator`)
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## How It Works
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On every server startup, `ensureSchema(db)` runs all pending migrations from the `apps/server/drizzle/` folder. Drizzle tracks applied migrations in a `__drizzle_migrations` table so only new migrations are applied. This is safe to call repeatedly.
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The migrator discovers migrations via `apps/server/drizzle/meta/_journal.json` — **not** by scanning the filesystem.
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## Workflow
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### Making schema changes
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1. Edit `apps/server/db/schema.ts` with your table/column changes
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2. Generate a migration:
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```bash
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npx drizzle-kit generate
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```
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3. Review the generated SQL in `apps/server/drizzle/NNNN_*.sql`
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4. Verify multi-statement migrations use `--> statement-breakpoint` between statements (required by better-sqlite3 which only allows one statement per `prepare()` call)
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5. Commit the migration file, snapshot, and journal update together
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### Important: statement breakpoints
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better-sqlite3 rejects SQL with multiple statements in a single `prepare()` call. Drizzle-kit splits on `--> statement-breakpoint`. If you hand-write or edit a migration with multiple statements, append `--> statement-breakpoint` to the end of each statement line (before the next statement):
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```sql
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ALTER TABLE foo ADD COLUMN bar TEXT;--> statement-breakpoint
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CREATE INDEX foo_bar_idx ON foo(bar);
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```
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### Applying migrations
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Migrations are applied automatically on server startup. No manual step needed.
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For tests, the same `ensureSchema()` function is called on in-memory SQLite databases in `apps/server/db/repositories/drizzle/test-helpers.ts`.
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## History
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Migrations 0000–0007 were generated by `drizzle-kit generate`. Migrations 0008–0032 were hand-written (the snapshots fell out of sync). A schema-derived snapshot was restored at 0032, so `drizzle-kit generate` works normally from that point forward.
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## Rules
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- **Use `drizzle-kit generate`** for new migrations. It reads schema.ts, diffs against the last snapshot, and generates both SQL + snapshot automatically.
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- **Never use raw CREATE TABLE statements** for schema initialization. The migration system handles this.
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- **Always commit migration files.** They are the source of truth for database evolution.
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- **Migration files are immutable.** Once committed, never edit them. Make a new migration instead.
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- **Keep schema.ts in sync.** The schema file is the source of truth for TypeScript types; migrations are the source of truth for database DDL. Both must reflect the same structure.
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- **Test with `npm test`** after generating migrations to verify they work with in-memory databases.
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