Start using Prisma in your existing database with Prisma introspection

This is a summary of what I’ll be presenting at Prisma Korea Meetup on Aug 28th.

If you are a javascript or typescript developer, I think you’ve already heard about Prisma, a next-generation ORM.

https://velog.io/@mgm-dev/Prisma2-%EB%9E%80-%EB%AC%B4%EC%97%87%EC%9D%B8%EA%B0%80

I’ve recently found few developers who wants to start using Prisma but their product is sticked to other orm like Sequelize. I also know how frustrating it is to switch ORM but this can be achieved pretty easily by Prisma’s introspection and I will tell what this is in this article.

Note that from Prisma 2.30.0, prisma instrospect command has changed to prisma db pull.

When I started using Sequelize in 2016 from the raw query, the experience was just great. It reduces bugs on typo and also provided more safe code by the static types and compile time errors. Therefore it saves much time on seeking through the runtime errors happening in raw sql queries.

The above is sample php raw query I used to work on

Above query is sample query using Sequelize ORM

It is pretty obvious to tell which one is more maintainable and also readable. In 2020, here it comes with Prisma. With Sequelize, you had to define each database table to sequelize models since they are active records.

In Prisma, you do not have to write for your models to start using its apis.

Imagine you have your own database system setup already. I will show you how Prisma instrospect database of existing service HackaTalk which is an opensource chat app.

Let’s clone the HackaTalk repository to create the database.

git clone https://github.com/dooboolab/hackatalk

Navigate to ./server and install packages.

Create a test user in your PostgreSQL database and copy test.env to .env in ./dotenv.

cp dotenv/test.env dotenv/.env

Finally, run yarn migrate:deploy to create hackatalk database in your local machine. The script will run the below command in your terminal.

dotenv -e ./dotenv/.env -- prisma migrate deploy

If you do not have done successfully, you will see the below tables when running npx prisma studio.

And below is how it looks in dbeaver.

Now, we have sample database to test Prisma Introspection.

What is introspection? (Reference)

Clone prisma-introspect-tutorial repository and create prisma/.env file. Then add below line of code.

DATABASE_URL="postgresql://test:test!@localhost:5432/test

Finally, run npx prisma introspect and see the result.

When you see schema.prisma file, you’ll see the generated models from introspection. This is awesome 🙌

Now, we will see what we can do with the generated schema.

1. Generate Prisma client from Prisma schema.

npx prisma generate

2. Open script.ts file and see what you get. You will see all the models appearing in auto-completion from the Prisma client.

You can immediately use prisma apis with your database records.

Prisma Introspection is really powerful!

You can introspect any database if they are supported by Prisma.

Sample of old database

It can also reduce your time to understand the database going through the schema.prisma file.

Finally, I want to share how you can migrate your database to other providers using multiple Prisma Clients.

I made three Prisma schemas each with different database providers, mongodb, mysql, and prostgresql.

MongoDB

MYSQL

POSTGRESQL

Run the below scripts to generate Prisma clients.

Finally, write the below code to copy rows of tables.

After running codes, you will end up having rows in each database.

MongoDB

MYSQL

You’ve successfully migrated to another database provider. You can also test these in prisma studio. I took a screenshot with different tools to verify that they are running on different database providers.

As you can see in the post, you can start using Prisma with minimal effort! The source code is here!

Start using Prisma today!! 🎉