Php登录系统-null值登录

Question

我使用MYSQL的PHP登录系统使用空值登录。为什么会发生这种情况？

session_start();

$username = $_POST['username'];
$password = $_POST['password'];


mysql_connect("localhost" , "root" , "");
mysql_select_db("deirastaff");

$result = mysql_query("SELECT * FROM users WHERE username ='$username' and password = '$password' ")

    or die("Login failed" .mysql_error());

$row = mysql_fetch_array($result);

if ($row['username']==$username && $row['password']==$password) {

   $_SESSION['username']=$username;

    echo '<script type="text/javascript"> window.open("staff.php","_self");</script>';

    //header("location:staff.php");

    //echo "Login Successfull "."Welcome ".$row['username'];    

}else {

    echo '<script type="text/javascript">
    window.alert("Login failed!");
    window.open("index.php","_self");
    </script>';

    //header("location:index.php");
    //echo "Login Failed !";
    break;
}

Answer 1

MySQLi更适合使用...

但是如果你想使用MySQL，那就试试下面的代码。

if(isset($submit)) //name of your submit button
{
    $result = mysql_query("SELECT * FROM users WHERE username ='$username' and password = '$password' ") or die("Login failed" .mysql_error());
    if(mysql_num_rows($rs)<1)
    {
        echo "Login Failed" ;
    }
    else
    {
        $_SESSION[username]=$username;
    }
}

Answer 2

在执行查询之前，您可以只检查您拥有的值。

if (!empty($row['username']) && !empty($row['password'])) { ... }

您还可以将用户名和密码表设置为不允许空值。