Ich lerne MySQL und PHP und habe derzeit Probleme mit diesem Anmeldevorgang.

Es scheint, dass die MySQL-Abfrage keine Zeilen zurückgibt und mich nach einer erfolgreichen Anmeldung nicht umleitet.

PHP:

$error_msg = "";
//checks the session to see if the user is logged in
if (!isset($_SESSION['userid'])) {
    if (!isset($_POST['submit'])) {
        $dbc = mysqli_connect('localhost', 'root', '', 'login')
        or die('Error Connecting to Database on the SQL Server');
        //grabs data from POST
        $user_username = $_POST['username'];
        $user_password = $_POST['password'];
        //lookup username and password in the database
        if (!empty($user_username) && !empty($password)) {
            $query = "SELECT userid, username FROM tuser WHERE username = '$user_username' AND password = SHA('$user_password')";
            $res = mysqli_query($dbc, $query);
            //login is ok so set the user ID and username cookies, redirect to homepage
            if (mysqli_num_rows($res) == 1) {
                $row = mysqli_fetch_array($res);
                $_SESSION['userid'] = $row['userid'];
                $_SESSION['username'] = $row['username'];
                setcookie('userid', $row['userid'], time() + (60 * 60 * 24 * 30), "/");
                setcookie('username', $row['username'], time() + (60 * 60 * 24 * 30), "/");
                setcookie('email', $row['email'], time() + (60 * 60 * 24 * 30), "/");
                setcookie('password', $row['password'], time() + (60 * 60 * 24 * 30), "/");
                //redirect after successful login
                header("Location: index.php");
            } else {
                //the username and password are incorrect so set error message
                $error_msg = 'Sorry, you must enter a valid username and password to log in. <a href="Signup.php">Please sign up!</a>';
            }
        }
    }
}

HTML:

<form action="login_process.php" method="post" class="login">
 Username: <input type="text" name="username"/>
 Password: <input type="password" name="password"/>
 <input type="submit" value="submit"/>
</form>

Entschuldigung für den schlampigen Code, ich kenne mich mit PHP und MySQL aus und bringe mir selbst bei, wie das geht. Ich habe einige Änderungen vorgenommen und der Code wird gesendet, aber er leitet mich nicht weiter. Er geht einfach zu login_process.php und führt nichts aus. Was vermisse ich? Ich danke Ihnen allen für Ihre Hilfe!

    <?
    session_start();

    $error_msg = "";

    //checks the session to see if the user is logged in

if (!isset($_SESSION['user_id'])) 
{
    if (isset($_POST['submit'])) 
    {

        $user_username = mysql_real_escape_string($_POST['username']);
        $user_password = mysql_real_escape_string($_POST['password']);

        $dbc = mysqli_connect('localhost', 'root', '', 'login')
        or die('Error Connecting to Database on the SQL Server');
        //grabs data from POST

            //lookup username and password in the database
            if (!empty($user_username) && !empty($password)) 
            {

                $query = "SELECT userid, username FROM tuser WHERE username = '$user_username' AND password = SHA('$user_password')";

                $res = mysqli_query($dbc, $query);

                //login is ok so set the user ID and username cookies, redirect to homepage
                if (mysqli_num_rows($res) == 1) 
                {
                    $row = mysqli_fetch_array($res);

                    $_SESSION['user_id'] = $row['userid'];
                    $_SESSION['user'] = $row['username'];
                    setcookie('userid', $row['userid'], time() + (60 * 60 * 24 * 30), "/");
                    setcookie('username', $row['username'], time() + (60 * 60 * 24 * 30), "/");
                    setcookie('email', $row['email'], time() + (60 * 60 * 24 * 30), "/");
                    setcookie('password', $row['password'], time() + (60 * 60 * 24 * 30), "/");

                    //redirect after successful login
                    header("Location: home.php");
                    echo mysqli_error($dbc);

                } 
                else 
                {
                    //the username and password are incorrect so set error message
                    $error_msg = 'Sorry, you must enter a valid username and password to log in. <a href="Signup.php">Please sign up!</a>';

                    header("Location: home.php");
                    echo mysqli_error($dbc);

                }
            }
            else
            {
                $error_msg = 'Please enter a username and password to log in. <a href="Signup.php">Please sign up!</a>';

                header("Location: home.php");
                echo mysqli_error($dbc);

            }

    }
}

    ?>