Untitled

<?php
session_start();
if (isset($_GET['logout'])) {
    unset($_SESSION['logged_in']);
}
?>

<html>
    <head>
        <title>PHP Sessions</title>
        <?php
        if (isset($_POST['submit'])){
            //print_r($_POST);
            $password = md5($_POST['password']);
            //echo'<p>'.$password.'</p>';
            $accts = array('student1'=>'5f4dcc3b5aa765d61d8327deb882cf9',
                           'student2'=>'5f4dcc3b5aa765d61d8327deb882cf9');
            $username = $_POST['username'];
            if (isset($accts[$username])){
                //echo '<p>username found!</p>';
                if ($accts[$username] == $password) {
                    //echo '<p>password matches!</p>';
                    $_SESSION['logged_in'] = $username;
                }
            }
        }
        ?>
    </head>
    <body>
    <?php
$db = new PDO('sqlite:login.sqlite');
$sql = 'CREATE TABLE login (
        userid VARCHAR (12) PRIMARY KEY,
        password VARCHAR(12)
);';
$table = $db->query($sql);
$sql1 = 'INSERT INTO login (userid, password)
        VALUES("student1","5f4dcc3b5aa765d61d8327deb882cf99");';
$insert = $db->query($sql1);
$testSql = 'SELECT userid, password FROM login;';

?>
    <?php
    if (!isset($_SESSION['logged_in'])){
    ?>
        <form method="post" action="db_test.php">
            <p>Username:<br /><input type="text" name="username" /> </p>
            <p>Password:<br /><input type="password" name="password" /></p>
            <p><input type="submit" name="submit" value="log in" /></p>
        </form>
    <?php
    } else {
    ?>
    <h1>Protected Content!</h1>
    <p>You are logged in as <em><?php echo $_SESSION['logged_in']; ?></em></p>
    <p><a href="New_Cars.php">Add a new car</a></p>
    <p><a href="Book_Out_Cars.php">Book out a car</a></p>
    <p><a href="db_test.php?logout=true">Log out</a></p>
    <?php
    }
    ?>