npm install @mikro-orm/seeder

# Run seeders
npx mikro-orm seeder:run

# Create a new seeder class
npx mikro-orm seeder:create DatabaseSeeder

import type { EntityManager } from '@mikro-orm/core';
import { Seeder } from '@mikro-orm/seeder';

export class DatabaseSeeder extends Seeder {
  async run(em: EntityManager): Promise<void> {
    const author = em.create(Author, {
      name: 'John Doe',
      email: '[email protected]',
    });

    em.create(Book, { title: 'My First Book', author });
  }
}

import { Factory } from '@mikro-orm/seeder';

export class AuthorFactory extends Factory<Author> {
  model = Author;

  definition(): Partial<Author> {
    return {
      name: `Author ${Math.random()}`,
      email: `author-${Math.random()}@example.com`,
    };
  }
}

// In your seeder:
const factory = new AuthorFactory(em);
const authors = factory.make(10); // create 10 Author instances