เกี่ยวกับตะกร้าสินค้าแบบ session ครับผม รบกวนให้คำปรึกษาหน่อยครับ

session_start();
	require_once("include/class.db.php");
	require_once("include/initail.php");
	$db = new DB("$hostname","$user","$pass","$dbase");
	$pro_id = $_REQUEST['pro_id'];
	if(!is_numeric($_POST['amount'])){exit("<script>alert('Please number input!!!');history.back();</script>");}
	session_register("sess_id");
	session_register("sess_name");
	session_register("sess_price");
	session_register("sess_num");
	if(count($sess_id) == "0"){
		$check = 1;
	}else if(!in_array($pro_id,$sess_id)){
		$check = 1;
	
	}
	
	if($check == 1){
		$select = $db->select("*","tb_product","pro_id = '$pro_id'","","","");
		$row = $db->fetch_arr($select);

		$sess_id[] = $row['pro_id'];
		$sess_name[] = $row['pro_name'];
		$sess_price[] = $row['pro_price'];
		$sess_num[] = $_POST['amount'];
		
	}
	exit("<script type=\"text/javascript\">window.location='basket.php';</script>");
	//	header("Location : basket.php");