利用PHP的OOP特性实现数据保护（3）

/**
*
* 执行当前query，并把占位符替换为所提供的参数。
*
* @param mixed $queryParams,... Query parameter
* @return resource A reference to the resource representing the executed query.
*/
public function execute($queryParams = '')
{
　//例如：SELECT * FROM table WHERE name=:1S AND type=:2I AND level=:3N
　$args = func_get_args();

　if ($this->stored_procedure) {
　　/* 调用函数compile以取得query */
　　$query = call_user_func_array(array($this, 'compile'), $args);
　} else {
　　/* 如果存储过程未被初始化，就把它作为标准query执行。*/
　　$query = $queryParams;
　}

　$this->result = $this->db->query($query);

　return $this->result;
}

require 'mysql_db.php5';
require_once 'query2.php5';


$db = new MySqlDb;
$db->connect('host', 'username', 'pass');
$db->query('use content_management_system');

$query = new DBQuery($db);

$query->prepare('SELECT fname,sname FROM users WHERE username=:1S AND pword=:2S AND expire_time<:3I');

if ($result = $query->execute("visualad", "apron", time())) {
　if ($db->num_rows($result) == 1) {
　　echo('凭证正确。');
　} else {
　　echo('凭证不正确，会话已过期。');
　}
} else {
　echo('执行query时发生错误：' . $db->error());
}