create a new factory for the Book model using the following Artisan command

php artisan make:factory BookFactory --model=Book

.it would generate a

 BookFactory.php

file under

database/factories 

which looks like so.

<?php

namespace Database\Factories;

use App\Models\Book;
use Illuminate\Database\Eloquent\Factories\Factory;
use Illuminate\Support\Str;

class BookFactory extends Factory
{
    /**
     * The name of the factory's corresponding model.
     *
     * @var string
     */
    protected $model = Book::class;

    /**
     * Define the model's default state.
     *
     * @return array
     */
    public function definition()
    {
        return [
            //
        ];
    }
}

define the definition method like so.

public function definition()
{
    return [
        'title' => $this->faker->name,
        'author' => $this->faker->name,
        'published' => 1
    ];
}

Using the factories Once the

BookFactory 

is created, it’s now ready to be used. For instance, we can use it in the

database/seeders/DatabaseSeeder.php

class like so.

<?php

namespace Database\Seeders;

use App\Models\Book;
use App\Models\User;
use Illuminate\Database\Seeder;

class DatabaseSeeder extends Seeder
{
    /**
     * Seed the application's database.
     *
     * @return void
     */
    public function run()
    {
        Book::factory(5)->create();
    }
}

Notice, you can now directly use the factory on the model instance (App\Models\Book in this case) that is because when you create a model using the

php artisan make:model Book

Artisan command in Laravel 8, it generates the model which includes the new

HasFactory

trait. So, our Book model looks like so.

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Book extends Model
{
    use HasFactory;
}