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How to migrate from TypeORM to Prisma ORM

15 min

Introduction​

This guide shows you how to migrate your application from TypeORM to Prisma ORM. We'll use an extended version of the TypeORM Express example as a sample project to demonstrate the migration steps.

This migration guide uses PostgreSQL as the example database, but it equally applies to any other relational database that's supported by Prisma ORM. You can learn how Prisma ORM compares to TypeORM on the Prisma ORM vs TypeORM page.

Prerequisites​

Before starting this guide, make sure you have:

  • A TypeORM project you want to migrate
  • Node.js installed (version 16 or higher)
  • PostgreSQL or another supported database
  • Basic familiarity with TypeORM and Express.js

2. Prepare for migration​

2.1. Understand the migration process​

The steps for migrating from TypeORM to Prisma ORM are always the same, no matter what kind of application or API layer you're building:

  1. Install the Prisma CLI
  2. Introspect your database
  3. Create a baseline migration
  4. Install Prisma Client
  5. Gradually replace your TypeORM queries with Prisma Client

These steps apply whether you're building a REST API (e.g., with Express, Koa, or NestJS), a GraphQL API (e.g., with Apollo Server, TypeGraphQL, or Nexus), or any other kind of application that uses TypeORM for database access.

2.2. Set up Prisma configuration​

Create a new Prisma schema file:

npx prisma init --output ../generated/prisma

Update the DATABASE_URL in the .env file with your database connection string:

DATABASE_URL="postgresql://USER:PASSWORD@HOST:PORT/DATABASE"

3. Migrate the database schema​

3.1. Introspect your database​

Run Prisma's introspection to create the Prisma schema from your existing database:

npx prisma db pull

This will create a schema.prisma file with your database schema.

3.2. Create a baseline migration​

Create and apply a baseline migration to mark the current state of your database:

npx prisma migrate diff --from-empty --to-schema-datamodel prisma/schema.prisma --script > baseline.sql
npx prisma migrate resolve --applied "baseline"

4. Update your application code​

4.1. Install Prisma Client​

Install the Prisma Client package:

npm install @prisma/client

Generate Prisma Client:

npx prisma generate

4.2. Replace TypeORM queries​

Start replacing your TypeORM queries with Prisma Client. Here's an example of how to convert some common queries:

// Find one
const user = await userRepository.findOne({ 
  where: { id: 1 } 
});

// Create
const user = await userRepository.save({
  email: 'alice@prisma.io',
  name: 'Alice'
});

// Update
await userRepository.update(1, { 
  name: 'New name' 
});

// Delete
await userRepository.delete(1);

4.3. Update your controllers​

Update your Express controllers to use Prisma Client. For example, here's how to update the CreateUserAction:

import { prisma } from '../client'

export class CreateUserAction {
  async run(req: Request, res: Response) {
    const { email, name } = req.body
    
    const result = await prisma.user.create({
      data: {
        email,
        name,
      },
    })
    
    return res.json(result)
  }
}

5. Test and deploy​

5.1. Test your changes​

Test all migrated endpoints to ensure they work as expected:

npm test

5.2. Deploy your changes​

  1. Deploy your schema changes:
npx prisma migrate deploy
  1. Deploy your application code with the updated dependencies.

Next steps​

Now that you've migrated to Prisma ORM, you can:

  • Add more complex queries using Prisma's powerful query API
  • Set up Prisma Studio for database management
  • Implement database monitoring
  • Add automated tests using Prisma's testing utilities

For more information:


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