# Database and Drizzle

`createDrizzleDatabase()` from `@neutron-build/data` resolves a database
profile and creates the matching Drizzle client.

## Install a driver

For PostgreSQL or Nucleus SQL:

```bash
npm install @neutron-build/data drizzle-orm postgres
```

For SQLite:

```bash
npm install @neutron-build/data drizzle-orm @libsql/client
```

## Connect

```ts
import { createDrizzleDatabase } from "@neutron-build/data";
import type { PostgresJsDatabase } from "drizzle-orm/postgres-js";
import * as schema from "./schema";

const database = await createDrizzleDatabase({
  config: { database: "postgres" },
  schema,
});
const db = database.db as PostgresJsDatabase<typeof schema>;

try {
  const users = await db.select().from(schema.users);
} finally {
  await database.close();
}
```

The returned object contains:

- `profile` — the selected provider and connection string.
- `db` — the Drizzle database instance.
- `client` — the underlying Postgres or libSQL client.
- `nucleus` — the optional multi-model client when using Nucleus.
- `close()` — closes the created clients.

The `db` and `client` fields are currently exposed as `unknown`; narrow them to
the installed driver's types, as in the example above.

## Select a provider

Pass a provider explicitly:

```ts
const database = await createDrizzleDatabase({
  config: { database: "postgres" },
  schema,
});
```

Without an explicit provider, selection checks `NUCLEUS_URL`, then
`DATABASE_URL`, then uses `.neutron/dev.db` with SQLite. Nucleus uses the
PostgreSQL driver for SQL and optionally creates an `@neutron-build/nucleus`
client for its other data models.