สอบถามเรื่องการ upload file ครับ คือ ติดปัญหาตอนเชคชื่อไฟล์ในตารางครับ แล้วอยากจะเปลี่ยนชื่อไฟล์

<?
$HTTP_POST_FILES ; 
session_start();
$path = "upload/".$_FILES['ufile']['name']; // path of file (in folder name "upload")
include("connect/connect.php");
$tbl_name="upload"; // Table name
$title = $_POST['title'];
$file_name = $_FILES['ufile']['name'];
$file_location = $path;
date_default_timezone_set('Asia/Bangkok');
$date = date("Y-m-d H:i:s", time()) ;
$upload_by = $_SESSION["myusername"];
$objOpen = opendir("upload");
$sql_check = "Select * from $tbl_name where file_name = '$file_name'";
// Check File Name in table
$result_check=mysql_query($sql_check);
$count=mysql_num_rows($result_check);
if($count==0){}
else{
$file_name = $_FILES['ufile']['name']."_".$upload_by;	
};


if
(move_uploaded_file($_FILES["ufile"]["tmp_name"],"upload/".$_FILES["ufile"]["name"]))
{
	echo "Upload File Successful<br/>";
	echo "<hr />";
	echo $title."<br/>";
	echo $date."<br/>";
	echo "<b>File Name :</b>"." " .$_FILES['ufile']['name']."<br/>"; // Show File Name
	echo "<b>File Size :</b>"." " .$_FILES['ufile']['size']."<br/>"; // Show File Size
	echo "<b>File Type :</b>"." " .$_FILES['ufile']['type']."<br/>"; // Show File Type
	echo "<img src=\"$path\" width=\"150\" height=\"150\">"; // Show Picture (Uploaded)
		$sql_up = "INSERT INTO $tbl_name
		(`Tiltle`, `File_Name`, `File_Location`, `Date`, `upload_by`)  
		VALUES
		(
		'$title',
		'$file_name',
		'$file_location',
		'$date',
		'$upload_by'
		)";
		$result=mysql_query($sql_up);
		if($result){echo "success";}
		else{
			?>
            <script language="javascript">
	alert("Cannot Save File Information to Database");
	</script>
            <?
			};


}else{
?>
<script language="javascript">
	alert("Cannot Upload File");
	</script><? } ?>