<center>
	<?php
		include ("database.php");
	?>

<?php

session_start();

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

$query = "select role from users where
	username = '$username' and
	password = '$password'";
$result = mysql_query ($query);
if(!$result)
{
echo 'Cannot run query.';
exit;
}
$row = mysql_fetch_assoc ($result);


if ($username = '')
{
echo 'You are not authorized to view this page.';
}
else
	{
		$_SESSION['username']=$username;
		$role=$row['role'];

		if ( $role == 1 )
		{
			header('Location: admin_center.php');
		}
		elseif ( $role == 2 )
		{
			header('Location: teacher_center.php');
		}
		else
		{
			header('Location: stundent_center.php');
		}

}
?>
</center>