防止SQL注入

 1 function checkStr($username){
 2         //自定义字符串规则
 3 } 
 4 
 5 function checkLogin($username,$password){
 6         
 7         $password = md5($password);
 8 
 9         $username = addslashes($username);//转义
10 
11         $sql = "select * from {$this->getTableName()} where u_username=‘{$username}‘ and u_password=‘{$password}‘";
12 
13         return $this->db_getRow($sql);
14 }