how to retrieve polymorphic relations and how model structure should be

Question

I have 3 models called Customer,Receiver and Legal. Each model can have only one card and I have created a Model called Card.

this is my cards table in database

id | cardable_id | cardable_type | number               |  ...
--------------------------------------------------------------------
1  |  1          |   Receiver    | 6221-0612-0410-4907  |  ...
2  |  5          |   Customer    | 6301-4569-7896-4563  |  ...
3  |  2          |   Legal       | 6748-8520-4569-9630  |  ...

My Card Model

namespace App;

use Illuminate\Database\Eloquent\Model;

class Card extends Model
{
    public function cardable()
    {
        return $this->morphTo();
    }
}

My Customer Model

namespace App;

use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
    public function card()
    {
        return $this->morphOne(Card::class,'cardable');
    }

}

My Legal Model

namespace App;

use Illuminate\Database\Eloquent\Model;

class Legal extends Model
{
    public function card()
    {
        return $this->morphOne(Card::class,'cardable');
    }
}

And My Receiver Model:

namespace App;

use Illuminate\Database\Eloquent\Model;

class Receiver extends Model
{
    protected $guarded = ['id'];

    public function card()
    {
        return $this->morphOne(Card::class,'cardable');
    }
}

In my routs in web.php for testing relations I wrote the code below:

Route::get('test',function () {
  $card = \App\Card::find(1);
  return $card->cardable;
});

and I faced following error:

Class 'Receiver' Not found.

And when I try to use inverse relation:

Route::get('test2',function () {
  $customer = \App\Customer::find(5); // a customer with id=5 does exist
  return $customer->card;
});

it returns null.
I'm trying to get an instance of card's owner using $card->cardable and also get an instance of card using $customer->card or $receiver->card or $legal->card
What am I missing? Is this the right relation I have chosen for my purpose?

Answer 1

cardable_type must be link to model like \App\Receiver