willaengine/app/ShoppingCart.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use App\Appended\Traites\GetDateAttributesTrait;
use Illuminate\Database\Eloquent\SoftDeletes;

class ShoppingCart extends Model
{
    use GetDateAttributesTrait, SoftDeletes;

    protected $fillable = ['quantity', 'user_id', 'payable_id', 'payable_type', 'details', 'business_id'];

    public function batch()
    {
        return $this->belongsTo('App\BatchShoppingCart');
    }
    public function getDetailsAttribute()
    {
        return json_decode($this->attributes['details'], true);
    }
    public function setDetailsAttribute($value)
    {
        $this->attributes['details'] = json_encode($value, JSON_UNESCAPED_UNICODE);
    }

    public function user()
    {
        return $this->belongsTo('App\User');
    }

    public function business_item_variation()
    {
        return $this->belongsTo('App\BusinessItemVariation');
    }

    public function business()
    {
        return $this->belongsTo('App\Business');
    }

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

}