php+mysql 实现身份验证代码

<?php
$uname=$_post["username"];
$pwd=$_post["password"];
$link = mysql_connect('localhost', 'root', '123456')
or die('could not connect: ' . mysql_error());
mysql_select_db('ruida') or die('could not select database');
// 执行 sql 查询
$query = 'select * from user';
$result = mysql_query($query) or die('query failed: ' . mysql_error());
while($row=mysql_fetch_array($result)){
if($uname==$row['username'] && $pwd==$row['password'])
{
//页面跳转
}
else
echo 'error!';}
// 释放结果集
mysql_free_result($result);
// 关闭连接
mysql_close($link);
?>