exchange-2.0/app/Models/ModelAttribute.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphTo;


class ModelAttribute extends Model
{
    protected $table = 'model_attributes';

    protected $fillable = [
        "name",
        "value"
    ];

    protected $casts = [
        "value" => "array"
    ];

    public function owner(): morphTo
    {
        return $this->morphTo();
    }

}