Seeders and foreign key relationships

It seems you should use for() method:

$application = Application::create([ ... ]);
Referrer::factory()->for($application)

https://laravel.com/docs/12.x/eloquent-factories#belongs-to-relationships

The application has a referrer_id - how do I populate that?

Please show your database migration and relations definition of models.

I will do tomorrow

I'm assuming you're designing a system where an Applicant can submit one or many Application and a Referrer can refer many Application.

• An Application belongs to an Applicant and a Referrer.
• An Applicant has many Application or an Applicant has one Application, depending on your requirements.
• A Referrer has many Application.

class Application extends Model
{
    public function applicant() {
        return $this->belongsTo(Applicant::class);
    }

    public function referrer() {
        return $this->belongsTo(Referrer::class);
    }
}

class Applicant extends Model
{
    // if applicant can submit multiple applications
    public function applications() {
        return $this->hasMany(Application::class);
    }

    // or if you want to limit to 1 application
    public function application() {
        return $this->hasOne(Application::class);
    }
}

class Referrer extends Model
{
    public function applications() {
        return $this->hasMany(Application::class);
    }
}

Then you can do something like this:

Application::factory()
    ->for(Applicant::factory())
    ->for(Referrer::factory())
    ->create();

// or if you already have existing `$applicant` and `$referrer` instances:

Application::factory()
    ->state([
        'applicant_id' => $applicant->id,
        'referrer_id' => $referrer->id,
    ])
    ->create();

Or, you can also define the relationships in the Application factory:

public function definition(): array
{
    return [
        'applicant_id' => Applicant::factory(),
        'referrer_id' => Referrer::factory(),
        ...
    ];
}

You really shouldn't use seeders for anything complex like this, they are usually only used for testing, and in some cases used to enter static data that is needed for the application.

If it is for testing you can use factories to create relations like that.

Here is an example

// In the UserFactory, create posts using the "posts" relationship method
$user = User::factory()
    ->has(Post::factory()->count(3), 'posts')
    ->create();

@pgogy I think you’ve over-complicated the problem. Wouldn’t “applicant” and “referrer” both be users or some other person-like entity? If so, you can just define two relations pointing to the same model, then:

Schema::create('applications', function (Blueprint $table) {
    $table->id();
    $table->foreignId('applicant_id')->constrained('users')->cascadeOnDelete();
    $table->foreignId('referrer_id')->constrained('users')->cascadeOnDelete();
    // Other application table columns...
});

You’d then define these relationships on your Application model:

class Application extends Model
{
    public function applicant(): BelongsTo
    {
        return $this->belongsTo(User::class, 'applicant_id');
    }

    public function referrer(): BelongsTo
    {
        return $this->belongsTo(User::class, 'referrer_id');
    }
}

And the inverse on your User model:

class User extends Authenticatable
{
    // ...

    public function applications(): HasMany
    {
        return $this->hasMany(Application::class, 'applicant_id');
    }

    public function referrals(): HasMany
    {
        return $this->hasMany(Application::class, 'referrer_id');
    }
}

Seeding would then be easy, so long as you set up your ApplicationFactory properly:

class ApplicationFactory extends Factory
{
    public function definition(): array
    {
        return [
            'applicant_id' => User::factory(),
            'referrer_id' => User::factory(),
            // Other application-related fields...
        ];
    }
}

class ApplicationSeeder extends Seeder
{
    public function run(): void
    {
        // Automatically create application model with applicant and referrer...
        Application::factory()->create();
    }
}

Think I have fixed it, I had gone wrong in making two foreign keys