Goals
On this page, you will learn how to:
- Install the Prisma CLI
- Set up Prisma using Docker
- Introspect your existing database and derive a datamodel
- Use the datamodel to configure your Prisma API
- Generate a Prisma client
- Read and write data using the Prisma client
Using your existing database with Prisma currently only works when using PostgreSQL or MongoDB databases. It is not yet supported for MySQL.
Install the Prisma CLI
The Prisma CLI is used for various Prisma workflows. You can install it using Homebrew or NPM:
brew tap prisma/prisma brew install prisma
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Install Docker
To use Prisma locally, you need to have Docker installed on your machine. If you don't have Docker yet, you can download the Docker Community Edition for your operating system here.
Set up Prisma
Run the following command to connect Prisma to your existing database:
prisma init hello-world
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This launches an interactive wizard. Here's what you need to do:
- Select Use existing database
- Select your database, either PostgreSQL or MongoDB
- Provide the connection details for your database (see below for more info)
- Select the Prisma Go client
- The host of your Postgres server, e.g.
localhost
. (When connecting to a local database, you might need to usehost.docker.internal
.) - The port where your Postgres server listens, e.g.
5432
. - The name of your Postgres database.
- The name of your Postgres schema, e.g.
public
. - The database user.
- The password for the database user.
- Whether your database server uses SSL, possible values are
true
andfalse
.
- Your MongoDB connection string, e.g.
http://user1:myPassword@localhost:27017/admin
. Note that this must include the database credentials as well as theauthSource
database that's storing the credentials of your MongoDB admin user (by default it is often calledadmin
). Learn more here. - The name of your MongoDB database.
If you're using MongoDB Atlas, you can find your connection string by clicking the CONNECT-button on your cluster overview page. It looks similar to this: mongodb+srv://user:pw@cluster0-sapwg.mongodb.net/test?retryWrites=true
.
Launch Prisma
To start Prisma and connect it to your database, run the following commands:
cd hello-world docker-compose up -d
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Prisma is now connected to your database and runs on http://localhost:4466
.
Deploy the Prisma datamodel
You now have the minimal setup ready to deploy your Prisma datamodel. Run the following command (this does not change anything in your database):
prisma deploy
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Launching the Prisma server may take a few minutes. In case the prisma deploy
command fails, wait a few minutes and try again. Also run docker ps
to ensure the Prisma Docker container is actually running.
Prepare Go application
touch index.go
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You'll be using dep for dependency management in this tutorial. Run the following command to create the required setup:
dep init
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Great, you're now ready to write some code and talk to your database programmatically!
Read and write data using the Prisma client
The API operations of the Prisma client depend on the datamodel that was generated from the database introspection. The following sample queries assume there is a User
type in the datamodel defined as follows:
type User {
id: ID! @unique
name: String!
}
If you don't have such a User
type, you need to adjust the following code snippets with a type that matches your datamodel.
Add the following code in index.go
:
package main import ( "context" "fmt" prisma "hello-world/generated/prisma-client" ) func main() { client := prisma.New(nil) ctx := context.TODO() // Create a new user name := "Alice" newUser, err := client.CreateUser(prisma.UserCreateInput{ Name: name, }).Exec(ctx) if err != nil { panic(err) } fmt.Printf("Created new user: %+v\n", newUser) // Fetch all users users, err := client.Users(nil).Exec(ctx) if err != nil { panic(err) } fmt.Printf("%+v\n", users) }
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Before executing the script, you need to ensure all dependencies are available. Run the following command:
dep ensure
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Now execute the script with the following command:
go run index.go
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Whenever you run the script with that command, a new user record is created in the database (because of the call to createUser
).
Feel free to play around with the Prisma client API and try out some of the following operations by adding the following code snippets to the file (at the end of the main
function) and re-executing the script:
id := "__USER_ID__" userById, err := client.User(prisma.UserWhereUniqueInput{ ID: &id, }).Exec(ctx)
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In some snippets, you need to replace the
__USER__ID__
placeholder with the ID of an actual user.