Seeding

Seeding allows you to consistently re-create the same data in your database and can be used to:

• Populate your database with data that is required for your application to start, such as a default language or currency.
• Provide basic data for validating and using your application in a development environment. This is particularly useful if you are using Prisma Migrate, which sometimes requires resetting your development database.

How to seed your database in Prisma ORM

Prisma ORM's integrated seeding functionality expects a command in the "seed" key in the migrations object of your prisma.config.ts. This can be any command, prisma db seed will just execute it. In this guide and as a default, we recommend writing a seed script inside your project's prisma/ folder and starting it with the command.

import "dotenv/config";
import { defineConfig, env } from "prisma/config";
export default defineConfig({
  schema: "prisma/schema.prisma",
  migrations: {
    path: "prisma/migrations",
    seed: "tsx prisma/seed.ts",
  },
  datasource: {
    url: env("DATABASE_URL"),
  },
});

Integrated seeding with Prisma Migrate

Database seeding happens when you run prisma db seed. With prisma db seed, you decide when to invoke the seed command. It can be useful for a test setup or to prepare a new development environment, for example.

Example seed scripts

Here we suggest some specific seed scripts for different situations. You are free to customize these in any way, but can also use them as presented here:

Seeding your database

• Create a new file named seed.ts. This can be placed anywhere within your project's folder structure. The example below places it in the /prisma folder.

• In the seed.ts file, import Prisma Client, initialize it and create some records. As an example, take the following Prisma schema with a User and Post model:

model User {
 id    Int    @id @default(autoincrement())
 email String @unique
 name  String
 posts Post[]
}

model Post {
 id        Int     @id @default(autoincrement())
 title     String
 content   String
 published Boolean
 user      User    @relation(fields: [userId], references: [id])
 userId    Int
}

Create some new users and posts in your prisma/seed.ts file:

import { PrismaClient } from "../prisma/generated/client";
const prisma = new PrismaClient();
async function main() {
  const alice = await prisma.user.upsert({
    where: { email: "alice@prisma.io" },
    update: {},
    create: {
      email: "alice@prisma.io",
      name: "Alice",
      posts: {
        create: {
          title: "Check out Prisma with Next.js",
          content: "https://www.prisma.io/nextjs",
          published: true,
        },
      },
    },
  });
  const bob = await prisma.user.upsert({
    where: { email: "bob@prisma.io" },
    update: {},
    create: {
      email: "bob@prisma.io",
      name: "Bob",
      posts: {
        create: [
          {
            title: "Follow Prisma on Twitter",
            content: "https://twitter.com/prisma",
            published: true,
          },
          {
            title: "Follow Nexus on Twitter",
            content: "https://twitter.com/nexusgql",
            published: true,
          },
        ],
      },
    },
  });
  console.log({ alice, bob });
}
main()
  .then(async () => {
    await prisma.$disconnect();
  })
  .catch(async (e) => {
    console.error(e);
    await prisma.$disconnect();
    process.exit(1);
  });

• Add typescript, tsx and @types/node development dependencies:

npm install -D typescript tsx @types/node

• Add the seed field to your prisma.config.ts file:

import "dotenv/config";
import { defineConfig, env } from "prisma/config";
export default defineConfig({
  schema: "prisma/schema.prisma",
  migrations: {
    path: "prisma/migrations",
    seed: "tsx prisma/seed.ts", 
  },
  datasource: {
    url: env("DATABASE_URL"),
  },
});

• To seed the database, run the db seed CLI command:

npx prisma db seed

We're using TypeScript here, but it's possible to do the same thing in vanilla JavaScript. The same steps would be followed, expect with a prisma/seed.js file (without types), and calling node prisma/seed.js instead of tsx.

Seeding your database via raw SQL queries

You can also make use of raw SQL queries in order to seed the database with data.

While you can use a plain-text .sql file (such as a data dump) for that, it is often easier to place those raw queries, if they're of short size, into the seed.js file because it saves you the hassle of working out database connection strings and creating a dependency on a binary like psql.

To seed additional data to the schema.prisma above, add the following to the seed.js (or seed.ts) file:

async function rawSql() {
  const result =
    await prisma.$executeRaw`INSERT INTO "User" ("id", "email", "name") VALUES (3, 'foo@example.com', 'Foo') ON CONFLICT DO NOTHING;`;
  console.log({ result });
}

and chain this function to the promise calls, such as the following change towards the end of the file:

main()
  .then(rawSql)
  .then(async () => {
    await prisma.$disconnect();
  })
  .catch(async (e) => {
    console.error(e);
    await prisma.$disconnect();
    process.exit(1);
  });

Seeding your database via any language (with a Bash script)

In addition to TypeScript and JavaScript, you can also use a Bash script (seed.sh) to seed your database in another language such as Go, or plain SQL.

The following example runs a Go script in the same folder as seed.sh:

#!/bin/sh
# -e Exit immediately when a command returns a non-zero status.
# -x Print commands before they are executed
set -ex
# Seeding command go
run ./seed/

The following example uses psql to run a SQL script in the same folder as seed.sh:

#!/bin/sh
# -e Exit immediately when a command returns a non-zero status.
# -x Print commands before they are executed
set -ex
# Seeding command
psql file.sql

User-defined arguments

prisma db seed allows you to define custom arguments in your seed file that you can pass to the prisma db seed command. For example, you could define your own arguments to seed different data for different environments or partially seeding data in some tables.

Here is an example seed file that defines a custom argument to seed different data in different environments:

import { parseArgs } from "node:util";

const options = {
  environment: { type: "string" },
};

async function main() {
  const {
    values: { environment },
  } = parseArgs({ options });

  switch (environment) {
    case "development":
      /** data for your development */
      break;
    case "test":
      /** data for your test environment */
      break;
    default:
      break;
  }
}

main()
  .then(async () => {
    await prisma.$disconnect();
  })
  .catch(async (e) => {
    console.error(e);
    await prisma.$disconnect();
    process.exit(1);
  });

You can then provide the environment argument when using prisma db seed by adding a delimiter — -- —, followed by your custom arguments:

npx prisma db seed -- --environment development

Going further

Here's a non-exhaustive list of other tools you can integrate with Prisma ORM in your development workflow to seed your database:

• Supabase community project
• Replibyte