สอบถามการคิวรี่ PHP จาก Database แบบ OOP หน่อยครับ

class clsDatabase
{
	private $charset = "UTF-8";
	private $rs;
	public function connectDB($host,$user,$pw,$db)
	{
		mysql_connect($host,$user,$pw,$db);
		mysql_query($this->charset);
		mysql_select_db($db);
	}

	public function qry($qryString)
	{
		$this->rs = mysql_query($qryString);
	}

	public function fetchArray()
	{
		return mysql_fetch_array($this->rs);
	}

	public function numrows()
	{
		return mysql_num_rows($this->rs);
	}
}

include_once("clsDatabase.php");
include_once("config.inc.php");
class UserDB{

	private $rs = array();

	public function getAllUsers()
	{
		$obj = new clsDatabase();
		$obj->qry("select * from users");
		return $obj->fetchArray();
	}
}

include_once("../../lib/clsUserDB.php");
$obj = new UserDB();
foreach($obj->getAllUsers() as $r)
{
	echo $r['userID'];
}