php写入数据库

include_once 'Conn.php';
if($_POST['Submit']){
$sql = "insert into guestbook (ID,userName,title,content,lastdate) values (NULL,'$_POST[userName]','$_POST[title]','$_POST[content]',now())";
echo $sql;
mysql_query($sql);
echo "成功";
}
?>

Conn.php

$conn=@mysql_connect("localhost","root","") or die ("连接错误");//数据库连接
mysql_select_db("newDB",$conn);//
mysql_query("SET NAMES gbk");
?>