ช่วยดูโค้ดการแก้ไขข้อมูลให้ด้วยนะครับ คือมันจไปทำการแทนที่อันที่มีอยู่อะครับ

<TABLE width="900" height="0" border="1" align="left">
<TR>
	<TD><TABLE width="900" height="0" border="0" align="left">
<TR bgcolor="#C0C0C0"><BR>
<form method=post action="AddDataProType.php">
<TR bgcolor="#C0C0C0"><font face="Angsana News" size=5 color="Black" ><B><CENTER>¢éÍÁÙÅ»ÃÐàÀ·ÊÔ¹¤éÒ</CENTER></TR>
<TR >
	<TD>&nbsp&nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="Black" >ÃËÑÊ»ÃÐàÀ·ÊÔ¹¤éÒ
			&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="#FFFFFF" ><input type=text  name=txtID_ProType size="30" maxlength="6" >**<BR>
			 &nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="Black" >ª×èÍ»ÃÐàÀ·ÊÔ¹¤éÒ
			&nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="#FFFFFF" ><input type=text  name=txtName_ProType size="30" maxlength="50" >**<BR><BR>
				&nbsp&nbsp&nbsp<input type=submit  value=ºÑ¹·Ö¡>			&nbsp<input type=Reset  value=¡àÅÔ¡>
	</TD>
	</form>
</TR>
</TABLE>

<TABLE width="900" height="0" border="0" align="left">
<TR bgcolor="#C0C0C0"><BR>
<form method=post action="UpdateDataProductType.php">
<TR bgcolor="#C0C0C0"><font face="Angsana News" size=5 color="Black" ><B><CENTER>á¡é䢢éÍÁÙÅ»ÃÐàÀ·ÊÔ¹¤éÒ</CENTER></TR>
<TR >
	<TD>&nbsp&nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="Black" >ÃËÑÊ»ÃÐàÀ·ÊÔ¹¤éÒ
			&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="#FFFFFF" ><input type=text  name=txtID_ProType size="30" maxlength="6" value="<?=$result["ID_ProType"]?>">**<BR>
			 &nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="Black" >ª×èÍ»ÃÐàÀ·ÊÔ¹¤éÒ
			&nbsp&nbsp&nbsp&nbsp<font face="Angsana News" size=5 color="#FFFFFF" ><input type=text  name=txtName_ProType size="30" maxlength="50" value="<?=$result["Name_ProType"]?>">**<BR><BR>
				&nbsp&nbsp&nbsp<input type=submit  value=ºÑ¹·Ö¡>			&nbsp<input type=Reset  value=¡àÅÔ¡>
	</TD>
	<input type= "hidden" name="txtIDOld_ProType" value="<?=$result["ID_ProType"]?>"> 
	</form>
</TR>
</TABLE>

<TABLE width="1110" height="0" border="0" align="left"><?//Êèǹ¢Í§ÊÔ¹¤éÒãËÁè?>
<TR >
	<TD>
	<?
			include ("connect.php");
			$ID_ProType = $_POST[txtID_ProType];//ÃËÑÊãËÁè
			$Name_ProType = $_POST[txtName_ProType];
			$IDOld_ProType = $result["ID_ProType"]; //ÃËÑÊà¡èÒ

			if(trim($_POST["txtID_ProType"]) == "")
			{
				echo "<script language='JavaScript' type='text/javascript'>alert('¡ÃسҡÃÍ¡ÃËÑÊ»ÃÐàÀ·ÊÔ¹¤éÒ')</script>";
				echo "<script>window.location='javascript:history.go(-1)'</script>";
			}  
			if(trim($_POST["txtName_ProType"]) == "")
			{
				echo "<script language='JavaScript' type='text/javascript'>alert('¡ÃسҡÃÍ¡ª×èÍ»ÃÐàÀ·ÊÔ¹¤éÒ')</script>";
				echo "<script>window.location='javascript:history.go(-1)'</script>";
			}
			$strSQL = "SELECT * FROM producttype WHERE ID_ProType = '".trim($result["ID_ProType"])."' ";
			$objQuery = mysql_query($strSQL);
			$objResult = mysql_fetch_array($objQuery);
			if($objResult)
			{
				echo "<script language='JavaScript' type='text/javascript'>alert('ÃËÑÊ»ÃÐàÀ·ÊÔ¹¤éÒ¹ÕéÁÕÍÂÙèã¹ÃкºáÅéÇ ¡Ãسһé͹ÃËÑÊ»ÃÐàÀ·ÊÔ¹¤éÒãËÁè')</script>";
				echo "<script>window.location='javascript:history.go(-1)'</script>";
			}else{
			$sql = "update producttype set ID_ProType='".$ID_ProType."', Name_ProType='".$Name_ProType."' WHERE ID_ProType = '".trim($_POST['txtID_ProType'])."' "; //update to database
			$objQuery = mysql_query($sql);
			if($objQuery)
			{
					echo "<script language='JavaScript' type='text/javascript'>alert('·èÒ¹ä´é·Ó¡ÒÃá¡é䢢éÍÁÙÅ»ÃÐàÀ·ÊÔ¹¤éÒà»ç¹·ÕèàÃÕºÃéÍÂáÅéÇ ¢Íº¤Ø³¤ÃѺ')</script>";
					echo "<script type='text/javascript'>window.location='ShowDataProductType.php'</script>";
			}else{
					echo "<script language='JavaScript' type='text/javascript'>alert('·èÒ¹äÁèÊÒÁÒöá¡é䢢éÍÁÙÅ»ÃÐàÀ·ÊÔ¹¤éÒä´é ¡ÃسҡÃÍ¡¢éÍÁÙÅãËé¶Ù¡µéͧáÅФú·Ø¡ªèͧ')</script>";
					echo "<script>window.location='javascript:history.go(-1)'</script>";			
			}
			}
?>
	</TD>
</TR>
</TABLE>