Drizzle Seed

[!NOTE] drizzle-seed can only be used with [email protected] or higher. Versions lower than this may work at runtime but could have type issues and identity column issues, as this patch was introduced in [email protected]

Documentation

The full API reference and package overview can be found in our official documentation

Overview

drizzle-seed is a TypeScript library that helps you generate deterministic, yet realistic, fake data to populate your database. By leveraging a seedable pseudorandom number generator (pRNG), it ensures that the data you generate is consistent and reproducible across different runs. This is especially useful for testing, development, and debugging purposes.

What is Deterministic Data Generation?

Deterministic data generation means that the same input will always produce the same output. In the context of drizzle-seed, when you initialize the library with the same seed number, it will generate the same sequence of fake data every time. This allows for predictable and repeatable data sets.

Pseudorandom Number Generator (pRNG)

A pseudorandom number generator is an algorithm that produces a sequence of numbers that approximates the properties of random numbers. However, because it's based on an initial value called a seed, you can control its randomness. By using the same seed, the pRNG will produce the same sequence of numbers, making your data generation process reproducible.

Benefits of Using a pRNG:

• Consistency: Ensures that your tests run on the same data every time.
• Debugging: Makes it easier to reproduce and fix bugs by providing a consistent data set.
• Collaboration: Team members can share seed numbers to work with the same data sets.

With drizzle-seed, you get the best of both worlds: the ability to generate realistic fake data and the control to reproduce it whenever needed.

Getting started

npm install drizzle-seed

You have to install drizzle-orm in order to use drizzle-seed.

npm install drizzle-orm

Basic Usage

In this example we will create 10 users with random names and ids

import { pgTable, integer, text } from "drizzle-orm/pg-core";
import { drizzle } from "drizzle-orm/node-postgres";
import { seed } from "drizzle-seed";

const users = pgTable("users", {
  id: integer().primaryKey(),
  name: text().notNull(),
});

async function main() {
  const db = drizzle(process.env.DATABASE_URL!);
  await seed(db, { users });
}

main();

Options

count

By default, the seed function will create 10 entities. However, if you need more for your tests, you can specify this in the seed options object

await seed(db, schema, { count: 1000 });

seed

If you need a seed to generate a different set of values for all subsequent runs, you can define a different number in the seed option. Any new number will generate a unique set of values

await seed(db, schema, { seed: 12345 });

Reset databases

With drizzle-seed, you can easily reset your database and seed it with new values, for example, in your test suites

// path to a file with schema you want to reset
import * as schema from "./schema.ts";
import { reset } from "drizzle-seed";

async function main() {
  const db = drizzle(process.env.DATABASE_URL!);
  await reset(db, schema);
}

main();

More examples are available in our official documentation