方便操作的命名范围scope

<?php
namespace Goods\Model;
use Think\Model;

class GoodsModel extends Model 
{
    protected $_scope = array(
        'normal' => array(
            'where' => array('is_on_sale' => 1),
            'order' => array('id' => 'desc')
        ),

        'latest' => array(
            'order' => 'create_time',
            'where' => 'is_on_sale=1'),
        ),
        'default' => array(
            'order' => "id desc"
        ),
    );
    public function test()
    {
        $this->scope()->select();//1.使用默认定义的范围default
        $this->scope('normal')->select();//2.使用nomal命名范围
        $this->scope('normal,latest')->select();//3.使用nomal和latest范围

        $this->normal()->select();//使用normal命名范围,同2
        $this->normal(array('limit'=>5))->select();//使用normal命名范围,加上limit 5的条件,同连贯方法limit一样
    }
}