> ## Documentation Index
> Fetch the complete documentation index at: https://chatjs.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Database

> PostgreSQL database management commands and schema workflow

## Overview

ChatJS uses **PostgreSQL** with **Drizzle ORM** for type-safe, schema-first database access. The schema is defined in `apps/chat/lib/db/schema.ts` — edit it to change the database structure.

***

## Database Management

Run these commands from the `apps/chat` directory:

```bash theme={null}
# Push schema changes directly to the database (dev only — no migration file)
bun db:push

# Open Drizzle Studio at https://local.drizzle.studio
bun db:studio

# Generate a migration file from schema changes
bun db:generate

# Run pending migration files against the database
bun db:migrate
```

* **`db:push`** — fastest for local iteration; skips migration files. Not safe for production.
* **`db:generate` + `db:migrate`** — the production workflow; creates a versioned SQL file and applies it.
* **`db:studio`** — inspect, query, and edit data via a browser UI.

***

## Schema Changes

All schema changes start in `apps/chat/lib/db/schema.ts`. After editing:

1. Run `bun db:generate` to produce a migration file in `drizzle/`.
2. Review the generated SQL to confirm the diff is correct.
3. Run `bun db:migrate` to apply it.

For production schema changes, use Neon branching to isolate the change first. See [Neon Branching](/cookbook/neon-branching).