數據對象映射模式,是將對象和數據存儲映射起來,對一個對象的操作會映射為對數據存儲的操作。
在代碼中實現數據對象映射模式,實現一個ORM類,將復雜的sql語句映射成對象屬性的操作。對象關系映射(Object Relational Mapping,ORM)
ha_cl表
Hacl.php
<?php namespace Baobab; class Hacl{ public $id; public $haclname; public $haclcode; public $hacls; protected $db;
function __construct($id){ $this->db = new \Baobab\Database\Mysqli(); $this->db->connect('127.0.0.1', 'root', '', 'test'); $res = $this->db->query("select * from ha_cl where id = {$id}"); $data = $res->fetch_assoc(); $this->id = $data['ID']; $this->haclname = $data['ha_cl_name']; $this->haclcode = $data['ha_cl_code']; $this->hacls = $data['hacls']; } function __destruct(){ $this->db->query("update ha_cl set ha_cl_code = '{$this->haclcode}', ha_cl_name = '{$this->haclname}', hacls = '{$this->hacls}' where ID = {$this->id} limit 1"); } }
Factory.php
<?php namespace Baobab; class Factory{ static function getHacl($id){ $key = 'user_'.$id; $user = \Baobab\Register::get($key);//表中id不同表示的是不同的對象 if(!$user){ $user = new \Baobab\Hacl($id); \Baobab\Register::set($key, $user); } return $user; } }
Register.php
<?php namespace Baobab; class Register{ protected static $objects; static function set($alias, $object){ self::$objects[$alias] = $object; } static function _unset($alias) { unset(self::$objects[$alias]); } static function get($name) { return self::$objects[$name]; } }
index.php
class Page{ function index(){ $hacl = Baobab\Factory::getHacl(13); $hacl->haclname = '測試名稱'; $this->test(); echo 'ok'; } function test(){ $hacl = Baobab\Factory::getHacl(13); $hacl->hacls = '測試內容'; } } $page = new Page(); $page->index();
使用工廠模式會多次創建對象Hacl,浪費資源,如果將對象作為參數傳遞,一方面會帶來額外的使用成本,另外如果很多地方都用到這個對象很容易發生錯誤,因此在工廠模式中使用注冊樹模式來解決這個問題。