[Thắc mắc] - load CSDL không được ?

Mình có đoạn code load DANH MỤC HẢNG SỮA. Nhưng bị lỗi chổ nào ấy..Bạn nào pro giúp mình với Crying or Very sad

trang database.php

Code:: <?php
class database
{
var $_sql='';
var $_connection='';
var $_cursor=null;

function database()
{
$this->_connection=@mysql_connect('localhost','root','');
if(!$this->_connection){
die("Khong the ket noi MySQL");
}
$db='ql_bansua';
if($db!='' && !mysql_select_db($db, $this->_connection))
{
die("Khong the mo CSDL $db:" .mysql_error());
}
}
function setQuery()
{
$this->_sql=$sql;
}

function loadAllRows(){
if(!($cur= $this->query()))
   return null;
   $array=array();
   while ($row = mysql_fetch_array($cur))
   {
   $arary[]=$row;
   }
   mysql_free_result($cur);
   return $array;
}

function Query()
{
$this->_cursor=mysql_query($this->_sql, $this->_connection);
return $this->_cursor;
}
function disconnect()
{
mysql_close($this->_connection);
}

}

?>

trang xl_hang_sua.php

Code:: <?php
include_once('database.php');
class xl_hang_sua extends database
{
function danh_sach_hang_sua()
{
$data = new database();
$data->setQuery(' SELECT * FROM hang_sua');
$result = $data->LoadAllRows();
$data->disconnect();
return $result;
}
}
?>

trang load

Code:: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>

<body>

<?php
include_once("xl_hang_sua.php");
include_once("xl_loai_sua.php");

$xl_hang_sua= new xl_hang_sua();
$xl_loai_sua=new xl_loai_sua();
?>

<table width="400" border="3" cellspacing="3" cellpadding="3">
<tr>
<td>DANH MUC HANG SUA </td>
</tr>
<tr>
<td>
<?php
$mang_hang_sua=$xl_hang_sua->danh_sach_hang_sua();
$n=count($mang_hang_sua);
if($n<=0)
{$ketqua= "khong coa sua" ; }
if ($n>0)
{
foreach ($mang_hang_sua as $row)
{
$ten_hang_sua=$row["Ten_hang_sua"];
echo $ten_hang_sua."<br>";
}
}

?>
</td>
</tr>
</table>
</body>
</html>