Question

I am getting this error: Column ‘Username’ cannot be null.

First of all I am using jQuery UI. I made a modal form for registering users.
Here an extraction from my JS:

if ( bValid ) {
    var form = $('#register_form');  
    var data = form.serialize();  
    $.post('index.php?section=register', data, function(response) { 
            alert(response);
            $( "#dialog_create_user_ok" ).dialog( "open" );
    });  
    $( this ).dialog( "close" );
}

This seems to work well. Checked it with firebug and I get the correct post values. Username=…&Password=…

Now an extraction from my register.php which is defined by section=register (used a Tutorial):

if ('POST' == $_SERVER['REQUEST_METHOD']) {
    if (!isset($_POST['Username'], $_POST['Password'])) {
        return INVALID_FORM;
    }
    //Check for already existing User
    $sql = 'SELECT
                ID
            FROM
                User
            WHERE
                Username = ?
            LIMIT
                1';
    $stmt = $db->prepare($sql);
    if (!$stmt) {
        return $db->error;
    }
    $stmt->bind_param('s', $Username);
    $stmt->execute();
    $stmt->store_result();
        if ($stmt->num_rows) {
        return 'User already exists.';
    }
    $stmt->close();
    //Add User
    $sql = 'INSERT INTO
                User(Username)
            VALUES
                (?)';
    $stmt = $db->prepare($sql);
    if (!$stmt) {
        echo "hier bin ich";
        return $db->error;
    }
    $stmt->bind_param('s', $Username);
    if (!$stmt->execute()) {
        return $stmt->error;
    }
    $UserID = $stmt->insert_id;
    //Update password for User
    $sql = 'UPDATE
                User
            SET
                Password = ?
            WHERE
                ID = ?';
    $stmt = $db->prepare($sql);
    if (!$stmt) {
        return $db->error;
    }
    $Hash = md5(md5($UserID).$Password);
    $stmt->bind_param('si', $Hash, $UserID);
    if (!$stmt->execute()) {
        return $stmt->error;
    }
    return showInfo('Added user.');
}
return $ret;

It’s really strange. This code worked for me today. Then I had to change folders to get a better structure and now this.

Btw. this is my table User (ID = primary key):
!
http://imageshack.us/photo/my-images/823/unbenanntjfz.jpg/

Answer 1

It looks like your code is binding $Username to your MySQL statements, which from the code provided is not defined.

Perhaps you meant to bind $_POST['Username']? Same thing with $Password later in the script.