Morph field doesn't have a default value when seeding factory relationship

Question

I have a Recipe and Review model:

class Recipe extends Model
{
    use HasFactory;

    protected $guarded = ['id'];

    public function reviews(): MorphToMany
    {
        return $this->morphToMany(Review::class, 'reviewable');
    }
}

class Review extends Model
{
    use HasFactory;

    protected $guarded = ['id'];
}

Each has a factory:

class RecipeFactory extends Factory
{
    protected $model = Recipe::class;

    public function definition()
    {
        return [
            'name' => $this->faker->sentence(5, true),
        ];
    }
}

class ReviewFactory extends Factory
{
    protected $model = Review::class;

    public function definition()
    {
        return [
            'review' => $this->faker->paragraphs(1, true),
        ];
    }
}

When I try to seed new test records using this:

Recipe::factory()->hasAttached(
    Review::factory()
        ->count(5)
);

I get the SQL error:

SQLSTATE[HY000]: General error: 1364 Field 'reviewable_type' doesn't have a default value

How do I get Laravel to fill in the correct morph reviewable_type and reviewable_id values when seeding the related records?

Answer 1

In my case, I have a program, and a form, the form can be attached to various tables.

When I created my seeder I would grab a program, create a form, and then got the error General error: 1364 Field 'formable_type' doesn't have a default value

I fixed this by updating my migration to use nullableMorphs.

$table->nullableMorphs('formable');

Hope that will help someone.