Database Seeding

Database seeding is a simple way to add data into your database. It is especially useful during development where you need to populate the database with sample data that you can develop against, but it is not limited to that. Seeders can contain static data that you don't want to include in a migration, like countries, or geo-coding tables, event or setting information, and more.

Database Seeders

Database seeders are simple classes that must have a run() method, and extend CodeIgniter\Database\Seeder. Within the run() method, the class can create any form of data that it needs to. It has access to the database connection and the forge through $this->db and $this->forge, respectively. Seed files must be stored within the app/Database/Seeds directory. The name of the file must match the name of the class.

<?php

namespace App\Database\Seeds;

use CodeIgniter\Database\Seeder;

class SimpleSeeder extends Seeder
{
    public function run()
    {
        $data = [
            'username' => 'darth',
            'email'    => 'darth@theempire.com',
        ];

        // Simple Queries
        $this->db->query('INSERT INTO users (username, email) VALUES(:username:, :email:)', $data);

        // Using Query Builder
        $this->db->table('users')->insert($data);
    }
}

Nesting Seeders

Seeders can call other seeders with the call() method. This allows you to easily use a central seeder, but organize the tasks into separate seeder files:

<?php

namespace App\Database\Seeds;

use CodeIgniter\Database\Seeder;

class TestSeeder extends Seeder
{
    public function run()
    {
        $this->call('UserSeeder');
        $this->call('CountrySeeder');
        $this->call('JobSeeder');
    }
}

You can also use a fully-qualified class name in the call() method, allowing you to keep your seeders anywhere the autoloader can find them. This is great for more modular code bases:

<?php

namespace App\Database\Seeds;

use CodeIgniter\Database\Seeder;

class SimpleSeeder extends Seeder
{
    public function run()
    {
        $this->call('UserSeeder');
        $this->call('My\Database\Seeds\CountrySeeder');
    }
}

Using Seeders

You can grab a copy of the main seeder through the database config class:

<?php

$seeder = \Config\Database::seeder();
$seeder->call('TestSeeder');

Using a Different Database Group

You can specify a different database group when obtaining a seeder instance by passing the group name as the first parameter:

<?php

$seeder = \Config\Database::seeder('group_name');
$seeder->call('TestSeeder');

When using call() to run child seeders, the database connection is automatically passed to them. This means child seeders will use the same connection as the parent seeder, unless they explicitly specify their own $DBGroup property.

If a seeder needs to always use a specific database group regardless of the parent seeder's connection, you can set the $DBGroup property in the seeder class:

<?php

namespace App\Database\Seeds;

use CodeIgniter\Database\Seeder;

class UserSeeder extends Seeder
{
    protected $DBGroup = 'group_name';

    public function run()
    {
        // ...
    }
}

The connection priority is:

1. If $DBGroup is set in the seeder class, that connection group is always used
2. Otherwise, if a connection was passed (from parent seeder via call() or from Database::seeder()), it is used
3. Otherwise, the default connection group is used

Command Line Seeding

You can also seed data from the command line, as part of the Migrations CLI tools, if you don't want to create a dedicated controller:

php spark db:seed TestSeeder

Creating Seeder Files

Using the command line, you can easily generate seed files:

php spark make:seeder user --suffix

The above command outputs the UserSeeder.php file located in the app/Database/Seeds directory.

You can supply the root namespace where the seed file will be stored by supplying the --namespace option:

For Unix:

php spark make:seeder MySeeder --namespace Acme\\Blog

For Windows:

php spark make:seeder MySeeder --namespace Acme\Blog

If Acme\Blog is mapped to the app/Blog directory, then this command will generate MySeeder.php in the app/Blog/Database/Seeds directory.

Supplying the --force option will overwrite existing files in the destination.