Laravel 8 - Factories & Foreign Keys - php

Question

I haven't been able to locate how to manage foreign keys when creating Factories and Seeders.
I have a users table and a blog_posts table. The blog_posts table has a foreign key user_id that references users.id. I would like to seed my database with users and blog posts.
I have seen how to create a new user for each seeded blog post with the following:
/**
* Define the BlogPost model's default state.
*
* #return array
*/
public function definition()
{
return [
'user_id' => User::factory(),
'created_at' => now(),
'updated_at' => now(),
'title' => $this->faker->words(5, true),
'body' => $this->faker->paragraphs(6, true)
];
}
...but I would like to reference existing users since I am performing the database seed like so:
/**
* Seed the application's database.
*
* #return void
*/
public function run()
{
$this->call([
UsersTableSeeder::class,
BlogPostsTableSeeder::class
]);
}

Answer 1

We can retrieve a random existing User and assign it in the BlogPost Factory as follows:
/**
* Define the BlogPost model's default state.
*
* #return array
*/
public function definition()
{
return [
'user_id' => User::inRandomOrder()->first()->id,
'created_at' => now(),
'updated_at' => now(),
'title' => $this->faker->words(5, true),
'body' => $this->faker->paragraphs(6, true)
];
}

Answer 2

Assuming your User model has a hasMany relationship called blogPosts, you could do the following:
User::factory()
->hasBlogPosts(6)
->create();
This would create your User and 6 associated BlogPosts.