Prisma ORM

Introduction to Prisma

Prisma is a next-generation object–relational mapper (ORM) that claims to help developers build faster and make fewer errors. Prisma takes a different approach to ORMs compared to traditional ORMs. It uses a custom Schema Definition Language (SDL) that automatically writes migrations and generates type-safe code.

It consists of the following parts:

• Prisma Client
• Prisma Migrate
• Prisma Studio

Step 1) Installation of node and express.

In this blog, we will be working inside of a Node.js application. We will be learning how to integrate Prisma — an ORM for Node.js, along with Express.

Lets get everything set up before we move any further. Make sure you have these following packages installed on your computer before continuing.

By downloading and installing Node.js, it will install npm alongside it, which is another package we will need for this project. You can check to make sure you have it installed with the following command.

npm -v

If for some reason you don’t have it installed, you can install npm globally with the following command.

npm install -g npm

We will now begin creating the actual Node.js app. I am using VS Code, but you can use whatever text editor or IDE you like.

Lets first create a folder for this project, you can call it whatever you want.

Navigate wherever you want your project to be located at on your computer and run the following command.

mkdir prisma-postgres

I am going to call it, prisma-postgres. Once you have created the folder, navigate inside of it in your terminal, I am going to be using the terminal inside of VS Code for the remainder of this blog.

The first thing we have to do is create the actual Node.js app, lets start by running the following command inside of our directory we just created.

npm init

It will give you a few prompts, just keep pressing enter for all of them. Once this is finished, you should see a package.json file in your directory.

We are now going to run the following command into the terminal to install express and node.

npm install express node

Now we can start working on our server.

Create a file in your main directory called index.js. We are going to set up a very basic express server for this project.

Express server setup

We are now going to install a dev dependency to run the server. Enter the following command into your terminal.

npm install nodemon -D

This makes it so we don’t have to restart the server every time we make changes to our app.

Lets go ahead and start our server up by running the following code in the terminal.

nodemon index.js

After running this command, we should see this output in the terminal. Our server is now running on localhost:3000

Terminal output after running nodemon index.js

Step 2) Setting up our database connection string.

We are now going to install another dependency so we can connect to our database. Run this command in the terminal.

npm install dotenv

Now create a file in your main directory called .env

We will use this file to connect to our database using our connection string.

We will use this formatted string to connect to our database

postgres://YourUserName:YourPassword@localhost:5432/prisma

Make sure to put your username and password in the string to be able to connect to your db.

Then, in our .env file, we will declare our DATABASE_URL variable and set it equal to our connection string like so.

Postgres connection string

Now all we have to do to finish setting up our env file and connection string is load it in our server. All we have to do is add two lines of code to our index.js to accomplish this.

Load environment variables into our server

As you can see, on line 2 we have required dotenv, and on line 5 we configured our env file. We have now loaded our .env file, and we should now be ready to connect to our database.

Step 3) Setting up Prisma.

We will start by installing the prisma client. Run the following command in the terminal.

npm install @prisma/client

We will now install prisma as a dev dependency.

npm install prisma -D

Now that we have prisma installed, we can now initialize it by running the follwing command in the terminal.

npx prisma init

This will generate a prisma folder with a file called prisma.schema inside of it. This file is where we will create our database models.

Lets create a user model with and id, name, email, and password in the prisma.schema file.

model User {
  id       Int @id @default(autoincrement())
  name     String
  email    String
  password String
}

Your schema file should now look like this.

User schema

Now that we have our model created in the schema file, we can now generate the prisma client by running the following command in the terminal. The prisma client is used to run queries on your db.

npx prisma generate

Now we will migrate our db which will create a sql file of our current schemas and sync our postgres db with any prisma schemas we have.

Run the following command in your terminal and enter any name you’d like when it prompts you for a migration name.

npx prisma migrate dev

Now we are ready to set up our prisma client to be used across our app. It is recommended by Prisma that we only create one instance of the prisma client and reuse it so we aren’t opening up a new db connection on every request to our database. You can read more about this here.

Create a folder in the main directory of our app called db. Inside of our db folder, create a file called prisma.js

We will use this file to create an instance of the prisma client, we will be able to reuse this instance across our whole app.

Put the following code in your prisma.js file.

Instantiate Prisma Client

Then we just have to import it wherever we want to use it. I am going to import it into the main server.

Import prisma client wherever you want to use it

Step 4) Adding data to the database.

If you have existing data that you want to add to your db, you can do so by seeding it, you can learn how to do this here.

In your terminal, type in the following command.

npx prisma studio

Prisma studio database view

We now have data in our database and are now ready to make queries to our database using the prisma client.

Step 5) Making queries to our Postgres database.

In our main server, index.js, we are going to create a user and insert it into our database, then we will get all the users in our database and send them to the frontend to be rendered.

Inside of our main route inside of our server, we are going to insert the following code. This code is responsible for creating a user and inserting it into our database.

await prisma.user.create({
  data: {
    name: "John Doe",
    email: "jondoe@gmail.com",
    password: "123456"
  }
})

Now, we are going to insert the date which are entered by the particular user.

app.post(`/form`, async (req, res) => {
  const { name, email, password } = req.body
  const result = await prisma.post.create({
    data: {
      name,
      email,
      password
    },
  })
  res.json(result)
})

We are then going to insert the following code right under it, this will be responsible for getting all the users that we have stored in the database.

const users = await prisma.user.findMany()

We are then going to get the names of all of the users and store them in a list.

const names = users.map((user) => user.name)

After putting all of this in the main server, inside of our home route, our index.js should look like this.

This wraps up this blog for setting up Prisma with a in an Express Node.js application with form handling.