willaengine/app/City.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use App\Appended\Traites\UpdateModels;
use Kalnoy\Nestedset\NodeTrait;

class City extends Model
{
  use UpdateModels;
  use NodeTrait;

  protected $fillable=['name_fa', 'name_en', 'type', 'capital_city', 'latitude', 'longitude', 'parent_id'];

  public function addresses ()
  {
    return $this->hasMany('App\Address');
  }

  public function business_items ()
  {
    return $this->hasMany('App\BusinessItem');
  }

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

  public function districts ()
  {
    return $this->hasMany('App\District');
  }

  public function destination_orders ()
  {
    return $this->hasMany('App\Orders', 'destination_city_id');
  }

  public function source_orders ()
  {
    return $this->hasMany('App\Orders', 'source_city_id');
  }

  public function parent()
  {
      return $this->belongsTo('App\City', 'parent_id');
  }
  public function children()
  {
      return $this->hasMany('App\City', 'parent_id');
  }

  public function cities ()
  {
      return $this->hasMany('App\City', 'parent_id');
  }

  public function province ()
  {
      return $this->belongsTo('App\City', 'parent_id');
  }
  protected function clearCacheItems(){
    Cache::forget('cities');
  }

}