jiqu-library-server/app/Models/Zone.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Zone extends Model
{
    public const TYPE_PROVINCE = 'province';
    public const TYPE_CITY = 'city';
    public const TYPE_AREA = 'area';

    /**
     * @var array
     */
    protected $fillable = [
        'name',
        'parent_id',
        'type',
    ];
}