Fatal error on prepared statement

Question

Updated...

I am writing prepared statements and I´m getting this error message:

Notice: Undefined index: username in C:\\Program Files (x86)\\EasyPHP-12.1\\www\\inlogg_och_lagar\\core.inc.php on line 34

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''' at line 1' in C:\\Program Files (x86)\\EasyPHP-12.1\\www\\inlogg_och_lagar\\core.inc.php:34 Stack trace: #0 C:\\Program Files (x86)\\EasyPHP-12.1\\www\\inlogg_och_lagar\\core.inc.php(34): PDOStatement->execute(Array) #1 C:\\Program Files (x86)\\EasyPHP-12.1\\www\\inlogg_och_lagar\\index.php(23): getuserrow('username') #2 {main} thrown in C:\\Program Files (x86)\\EasyPHP-12.1\\www\\inlogg_och_lagar\\core.inc.php on line 34

Can someone tell me what I am doing wrong? It´sa simple login script.

Here is the loginform.inc.php

    <?php 
        if (isset($_POST['username'])&&isset($_POST['password'])) {

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

        $password_hash = md5 ($password);   


        if ($username && $password)
        {     
          $query  ="SELECT * FROM USERDATA where `username` = :username AND `password` = :password";
$stmt = $pdo->prepare($query);
$stmt->execute(array(
   ':username' => $_POST['username'],
   ':password' => $password_hash
));

$row = (bool) $stmt->fetch();
            if (!$rows)
            {   
                  echo '<p class="warning">Fel användarnamn/lösenords kombination.</p>';
            } else {    
                $_SESSION['user_id'] = $row;
                header('Location: index.php');
                exit;
            }
        } else {    
              echo '<p class="warning">Du måste fylla i ett användarnamn och lösenord</p>';
            }
    }
    ?>

        <!--- LOGIN FORM --->
        <div id="form-column">
            <p>You need to be loggedin.</p>
            <p>Fill out username and password.</p>
            <form action="<?php echo $current_file; ?>" method="POST"> 
                Användarnamn: <input type="text" name="username"> 
                Lösenord: <input type="password" name="password">
                <input type="submit" value="Log in">
            </form>
        </div>

Here is the core.inc.php

    <?php 
    ob_start();
    session_start();
    $current_file = $_SERVER['SCRIPT_NAME'];

    if (isset($_SERVER['HTTP_REFERER'])&&!empty($_SERVER['HTTP_REFERER'])) {
        $http_referer = $_SERVER['HTTP_REFERER'];
    }


    function loggedin () {
        if (isset($_SESSION['user_id'])&&!empty($_SESSION['user_id'])) {
            return true;
        }   else {
            return false;
        }
    }

    function getuserrow ($row) {
    $sql  ="SELECT * FROM USERDATA where id = ?".$_SESSION['user_id']."'";
    global $pdo;
    $stmt = $pdo->prepare($sql);
    $stmt->execute(array($_POST['username']));
    $row = $stmt->fetch();
}

    ?>

And here is the connect.inc.php

<?php

$dsn = "mysql:host=localhost;dbname=users;charset=utf8";
$opt = array(
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
);
$pdo = new PDO($dsn,'root','', $opt);

?>

Answer 1

Your PDO object is defined as $pdo , but later referenced as $dbh :

• From connect.inc.php :

   $pdo = new PDO($dsn,'root','', $opt); 

• From loginform.inc.php :

   global $dbh; // ... $stmt = $dbh->prepare($sql); 

Furthermore, loginform.inc.php does not appear to include connect.inc.php .

Answer 2

You are missing second parameter at $stmt->execute(array($_POST['username'])) it should be

$sql  ="SELECT * FROM USERDATA where username = ? AND password = ?";
$stmt = $pdo->prepare($sql);
$stmt->execute(array($_POST['username'], md5($_POST['password'])));//<== here

Answer 3

Replace this,

global $pdo;  // <- You don't need this one
$sql  ="SELECT * FROM USERDATA where username = ? AND password = ?";
$stmt = $pdo->prepare($sql);
$stmt->execute(array($_POST['username']));
$row = $stmt->fetch();

with

$query  ="SELECT * FROM USERDATA where `username` = :username AND `password` = :password";
$stmt = $pdo->prepare($query);
$stmt->execute(array(
   ':username' => $_POST['username'],
   ':password' => $password_hash
));

$row = (bool) $stmt->fetch();

In order to avoid situations like this one, you'd better stick with named placeholders instead of unnamed ones (like ? ).