yuan/application/common/model/City.php

<?php

namespace app\common\model;

use think\Cache;
use think\Model;

/**
 * 地区数据模型
 */
class City extends Model
{
    protected $name = 'city';

    public function park()
    {
        return $this->hasMany('app\common\model\park','c_id','id');
    }
}