关于析构函数的一个问题

[TheDean]

<?php

class test{
	public $id;
	public $name;
	public $mobile;
	public $regtime;

	function __construct(){
		
		@$conn=mysql_connect('localhost','root','123456789');
		$db=mysql_select_db('design');
		$res=mysql_query("select * from user where `id`=1");
		$data=mysql_fetch_assoc($res);
		$this->id=$data['id'];
		$this->name=$data['name'];
		$this->mobile=$data['mobile'];
		$this->regtime=$data['regtime'];
	}

	function __destruct(){
		mysql_query("update user set `regtime`='{$this->regtime}',`mobile`='{$this->mobile}',`name`='{$this->name}'  where `id`='{$this->id}' LIMIT 1");
	}
}
	class Page{
		function index(){
			$user1 = new test();
			$user1->name='tom';
			
			$this->test();
	
		}

		function test(){
			$user2= new test();
			$user2 ->mobile='333333333';
		}

	}

	$Page=new Page();
	$Page->index();

这是看慕课视频设计模式中的一个例子，为什么$user2 ->mobile='333333333';这句话是不会插进数据库的？