Prisma

Snappy loves Prisma

This example shows how to set up your Seed workflow with Prisma (opens in a new tab).

Prerequisites

Set up a new Prisma project by following the Prisma Quickstart (opens in a new tab) guide.

1. Install Seed

Set up Seed in your Prisma project by running the following command:

>_ terminal


npx @snaplet/seed init

2. Configure Seed

Using the previous command should have created a seed.config.ts configuration file.

You can use it as is, or customize it to fit your needs.

seed.config.ts


import { SeedPrisma } from "@snaplet/seed/adapter-prisma";
import { defineConfig } from "@snaplet/seed/config";
import { PrismaClient } from "@prisma/client";
export default defineConfig({
  adapter: () => {
    const client = new PrismaClient();
    return new SeedPrisma(client);
  },
  select: [
    "!*_prisma_migrations",
  ],
});

3. Customize the Seed Script

The npx @snaplet/seed init command should also have created a seed script example seed.ts.

You can move this file into your prisma directory and customize it to seed your database with the data you need.

prisma/seed.ts


import { createSeedClient } from "@snaplet/seed";
const seed = await createSeedClient();
// Truncate all tables in the database
await seed.$resetDatabase();
// Seed the database with 10 users
await seed.users((x) => x(10));
process.exit();

4. Hook into Prisma seeding workflow

You can hook into Prisma seeding workflow (opens in a new tab) by specifying a seed command in your package.json file:

package.json


"prisma": {
  "seed": "npx tsx prisma/seed.ts"
},

With this change, the database will be seeded with the data you specified in your seed.ts file for each of the following commands:

prisma db seed
prisma migrate dev
prisma migrate reset

5. Keep Seed Client in sync with your database

Whenever your database structure changes (e.g after a new migration is applied), @snaplet/seed will need be regenerated to reflect the new structure. To do this, run the following command:

>_ terminal


npx @snaplet/seed sync

If you want to automate this process, you can add a post script (opens in a new tab) to your package.json file:

package.json


"scripts": {
  "migrate": "prisma migrate dev",
  "postmigrate": "npx @snaplet/seed sync"
}

Recipes

@map and @@map renaming with Prisma in Snaplet Seed

In Prisma, you have the flexibility to rename tables and columns in the database using the @@map and @map annotations. This feature allows developers to map their model and field names in Prisma to different database table and column names. However, when using Snaplet Seed, it's important to note that Snaplet Seed operates directly with database table names, not Prisma model names. Below, we illustrate how to align Snaplet Seed's operations with your Prisma schema through alias overrides.

Default Prisma and Database Configuration

Here's how a typical Prisma model might be set up without any renaming:


model UserProfile {
  id          String      @id @default(uuid())
  createdAt   DateTime    @default(now())
}

This would correspond to the following SQL table creation:


CREATE TABLE "UserProfile" (
    "id" TEXT NOT NULL PRIMARY KEY,
    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

And it's used in @snaplet/seed like this:


await seed.UserProfile((x) => x(10, {
  createdAt: new Date(),
}));

Customizing Table and Column Names

You can customize the names in Prisma using @@map for tables and @map for columns:


model UserProfile {
  id          String      @id @default(uuid())
  createdAt   DateTime    @default(now()) @map("created_at")
  @@map("user_profile")
}

This reflects the following changes in your SQL schema:


CREATE TABLE "user_profile" (
    "id" TEXT NOT NULL PRIMARY KEY,
    "created_at" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

Subsequently, Snaplet Seed would access this table as:


await seed.user_profile((x) => x(10, {
  created_at: new Date(),
}));

Aligning Snaplet Seed with Prisma Mappings

To use Prisma-style naming in Snaplet Seed, adjust your seed.config.ts using alias overrides:


export default defineConfig({
  alias: {
    override: {
      user_profile: {
        name: 'UserProfile',
        fields: {
          created_at: "createdAt"
        }
      }
    }
  },
  adapter: () => {
    const client = new PrismaClient();
    return new SeedPrisma(client);
  },
  select: ["!*_prisma_migrations"],
});

After updating your configuration, run npx @snaplet/seed sync to apply the changes. Now, you can continue using the Prisma model names and conventions in Snaplet Seed:


await seed.UserProfile((x) => x(10, {
    createdAt: new Date()
}))

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