# Use Prisma Postgres with Bun

<Steps>
	<Step title="Create a new project">
		First, create a directory and initialize it with `bun init`.

    	```bash terminal icon="terminal"
    	mkdir prisma-postgres-app
    	cd prisma-postgres-app
    	bun init
    	```
    </Step>

    <Step title="Install Prisma dependencies">
    	Then install the Prisma CLI (`prisma`), Prisma Client (`@prisma/client`), and the Postgres driver adapter (`@prisma/adapter-pg`) as dependencies.

    	```bash terminal icon="terminal"
    	bun add -d prisma
    	bun add @prisma/client @prisma/adapter-pg
    	```
    </Step>

    <Step title="Initialize Prisma with PostgreSQL">
    	Use the Prisma CLI with `bunx` to initialize the schema and migration directory, with PostgreSQL as the database.

    	```bash terminal icon="terminal"
    	bunx --bun prisma init --db
    	```

    	This creates a basic schema. Update it to use the Rust-free client optimized for Bun: open `prisma/schema.prisma` and modify the generator block, then add a `User` model.

    	```prisma prisma/schema.prisma icon="/icons/ecosystem/prisma.svg"
    	generator client {
    		provider = "prisma-client"
    		output = "../generated/prisma" // [!code --]
    		output = "./generated" // [!code ++]
    		engineType = "client" // [!code ++]
    		runtime = "bun" // [!code ++]
    	}

    	datasource db {
    		provider = "postgresql"
    	}

    	model User { // [!code ++]
    		id    Int     @id @default(autoincrement()) // [!code ++]
    		email String  @unique // [!code ++]
    		name  String? // [!code ++]
    	} // [!code ++]
    	```
    </Step>

    <Step title="Configure database connection">
    	Set up your Postgres database URL in the `.env` file.

    	```ini .env icon="settings"
    	DATABASE_URL="postgresql://username:password@localhost:5432/mydb?schema=public"
    	```
    </Step>

    <Step title="Create and run database migration">
    	Then generate and run the initial migration.

    	The command writes a `.sql` migration file to `prisma/migrations` and executes it against your Postgres database. Bun [does not load `.env` automatically](/runtime/environment-variables) when it runs a CLI with `--bun`. The `prisma.config.ts` generated by `prisma init` reads `DATABASE_URL` from the environment, so pass `--env-file=.env` explicitly.

    	```bash terminal icon="terminal"
    	bun run --bun --env-file=.env prisma migrate dev --name init
    	```

    	```txt
    	Loaded Prisma config from prisma.config.ts.

    	Prisma schema loaded from prisma/schema.prisma.
    	Datasource "db": PostgreSQL database "mydb", schema "public" at "localhost:5432"

    	Applying migration `20250114141233_init`

    	The following migration(s) have been created and applied from new schema changes:

    	prisma/migrations/
    	  └─ 20250114141233_init/
    	    └─ migration.sql

    	Your database is now in sync with your schema.
    	```
    </Step>

    <Step title="Generate Prisma Client">
    	`prisma migrate dev` does not generate the _Prisma client_, so generate it with the Prisma CLI. The client provides a fully typed API for reading and writing to the database.

    	```sh terminal icon="terminal"
    	bun run --bun --env-file=.env prisma generate
    	```
    </Step>

    <Step title="Initialize Prisma Client with the Postgres adapter">
    	Create a new file `prisma/db.ts` that initializes the PrismaClient with the Postgres adapter.

    	```ts prisma/db.ts icon="/icons/typescript.svg"
    	import { PrismaClient } from "./generated/client";
    	import { PrismaPg } from "@prisma/adapter-pg";

    	const adapter = new PrismaPg({ connectionString: process.env.DATABASE_URL! });
    	export const prisma = new PrismaClient({ adapter });
    	```
    </Step>

    <Step title="Create a test script">
    	Write a script that creates a new user, then counts the users in the database.

    	```ts index.ts icon="/icons/typescript.svg"
    	import { prisma } from "./prisma/db";

    	// create a new user
    	await prisma.user.create({
    	  data: {
    	    name: "John Dough",
    	    email: `john-${Math.random()}@example.com`,
    	  },
    	});

    	// count the number of users
    	const count = await prisma.user.count();
    	console.log(`There are ${count} users in the database.`);
    	```
    </Step>

    <Step title="Run and test the application">
    	Run the script with `bun run`. Each run creates a new user.

    	```bash terminal icon="terminal"
    	bun run index.ts
    	```

    	```txt
    	There are 1 users in the database.
    	```

    	```bash terminal icon="terminal"
    	bun run index.ts
    	```

    	```txt
    	There are 2 users in the database.
    	```

    	```bash terminal icon="terminal"
    	bun run index.ts
    	```

    	```txt
    	There are 3 users in the database.
    	```
    </Step>

</Steps>

---

Prisma Postgres is now set up with Bun. Refer to the [official Prisma Postgres docs](https://www.prisma.io/docs/postgres) as you continue to develop your application.