PHP design pattern DAO (data access object pattern)

Data Access Object (Data Access Object) example, friends who learn PHP can refer to it.

The code is as follows:

<?php 
/** 
* 数据访问对象(Data Access Object) 示例 
* 
* @create_date: 2010-01-04 
*/ 
class BaseDAO 
{ 
var $_db = null; 
var $_table = null; 
function BaseDAO($config) 
{ 
$this->_db = new MysqlDB(); // 这里的不能进行操作 
} 
/** 
* 获取处理 
* 
* @param array $filter // 过滤条件 
* @param string $field // 获取字段 
* @param int $page // 当前页 
* @param int $limit // 页数 
*/ 
function fetch($filter = array(),$field = "*",$page = 1,$limit = null) 
{ 
$this->_db->select($filed)->from($this->_table)->where($filter)->limit($page,$limit); 
return $this->_db->execute(); 
} 
function update(){} 
function delete(){} 
function insert(){} 
} 
class MemberDAO extends BaseDAO 
{ 
var $_table = "member"; 
} 
$oMember = new MemberDAO(); 
$oMember->fetch(); 
/** 
* 常用到的地方: 
* MVC中model层基类 
*/ 
?>