How to Seed Data in Adonis.js

Database seeding in Adonis.js allows you to populate your database with initial or sample data, which is especially useful for development and testing.

Creating a Seeder

1. Generate a seeder file using the Ace CLI:

   node ace make:seeder User
   

   This will create a file in database/seeders/, e.g., UserSeeder.ts.

2. Edit the seeder file to define the data you want to insert. A typical seeder extends BaseSeeder and implements a run method:

   import BaseSeeder from '@ioc:Adonis/Lucid/Seeder'
   import User from 'App/Models/User'
   
   export default class UserSeeder extends BaseSeeder {
     public async run () {
       await User.create({
         email: 'example@adonisjs.com',
         password: 'secret',
       })
     }
   }
   

   You can also use methods like updateOrCreateMany to avoid duplicating records.

Running Seeders

• Run all seeders:

  node ace db:seed
  

  This command executes the run method of every seeder in the database/seeders directory.

• Run a specific seeder file:

  node ace db:seed --files "./database/seeders/UserSeeder.ts"
  

  You can use the --files flag multiple times to specify more than one seeder.

• Interactive mode:

  node ace db:seed -i
  

  This lets you select which seeders to run interactively.

• Specify a database connection:

  node ace db:seed --connection=your_connection_name
  

  The connection is passed to the seeder and can be used for model operations.

Additional Notes

• Seeders are typically used in development and testing environments.
• You can combine seeders with factories to generate large amounts of dummy data.
• Running seeders in production should be done with caution, and you may need to use the --force flag.

Summary:
To seed data in Adonis.js, create a seeder file, define your data in the run method, and execute node ace db:seed to populate your database.