Simple TypeScript Script Example

This example shows how to use Prisma Client in a simple TypeScript script to read and write data in a SQLite database. You can find the database file with some dummy data at ./prisma/dev.db.

How to use

1. Download example & install dependencies

Clone this repository:

git clone git@github.com:prisma/prisma-examples.git --depth=1

Install npm dependencies:

cd prisma-examples/typescript/script
npm install

Note that this also generates Prisma Client JS into node_modules/@prisma/client via a postinstall hook of the @prisma/client package from your package.json.

2. Run the script

Execute the script with this command:

npm run dev

Evolving the app

Evolving the application typically requires four subsequent steps:

1. Migrating the database schema using SQL
2. Update your Prisma schema by introspecting the database with prisma introspect
3. Generating Prisma Client to match the new database schema with prisma generate
4. Use the updated Prisma Client in your application code

For the following example scenario, assume you want to add a "profile" feature to the app where users can create a profile and write a short bio about themselves.

1. Change your database schema using SQL

The first step would be to add a new table, e.g. called Profile, to the database. In SQLite, you can do so by running the following SQL statement:

CREATE TABLE "Profile" (
  "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
  "bio" TEXT,
  "user" INTEGER NOT NULL UNIQUE REFERENCES "User"(id) ON DELETE SET NULL
);

To run the SQL statement against the database, you can use the sqlite3 CLI in your terminal, e.g.:

sqlite3 dev.db \
'CREATE TABLE "Profile" (
  "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
  "bio" TEXT,
  "user" INTEGER NOT NULL UNIQUE REFERENCES "User"(id) ON DELETE SET NULL
);'

Note that we're adding a unique constraint to the foreign key on user, this means we're expressing a 1:1 relationship between User and Profile, i.e.: "one user has one profile".

While your database now is already aware of the new table, you're not yet able to perform any operations against it using Prisma Client. The next two steps will update the Prisma Client API to include operations against the new Profile table.

2. Introspect your database

The Prisma schema is the foundation for the generated Prisma Client API. Therefore, you first need to make sure the new Profile table is represented in it as well. The easiest way to do so is by introspecting your database:

npx prisma introspect

Note: You're using npx to run Prisma 2 CLI that's listed as a development dependency in package.json. Alternatively, you can install the CLI globally using npm install -g @prisma/cli. When using Yarn, you can run: yarn prisma dev.

The introspect command updates your schema.prisma file. It now includes the Profile model and its 1:1 relation to User:

model Post {
  author    User?
  content   String?
  id        Int     @id
  published Boolean @default(false)
  title     String
}

model User {
  email   String   @unique
  id      Int      @id
  name    String?
  post    Post[]
  profile Profile?
}

model Profile {
  bio  String?
  id   Int     @default(autoincrement()) @id
  user Int     @unique
  User User    @relation(fields: [user], references: [id])
}

3. Generate Prisma Client

With the updated Prisma schema, you can now also update the Prisma Client API with the following command:

npx prisma generate

This command updated the Prisma Client API in node_modules/@prisma/client.

4. Use the updated Prisma Client in your application code

You can now use your PrismaClient instance to perform operations against the new Profile table. Here are some examples:

Create a new profile for an existing user

const profile = await prisma.profile.create({
  data: {
    bio: "Hello World",
    user: {
      connect: { email: "alice@prisma.io" },
    },
  },
});

Create a new user with a new profile

const user = await prisma.user.create({
  data: {
    email: "john@prisma.io",
    name: "John",
    profile: {
      create: {
        bio: "Hello World",
      },
    },
  },
});

Update the profile of an existing user

const userWithUpdatedProfile = await prisma.user.update({
  where: { email: "alice@prisma.io" },
  data: {
    profile: {
      update: {
        bio: "Hello Friends",
      },
    },
  },
});

Next steps

• Read the holistic, step-by-step Prisma Framework tutorial
• Check out the Prisma Framework docs (e.g. for data modeling, relations or the Prisma Client API)
• Share your feedback in the prisma2-preview channel on the Prisma Slack
• Create issues and ask questions on GitHub
• Track Prisma 2's progress on isprisma2ready.com