Help with deleting rows in database

[svgmx5]

I'm trying to delete rows in the database, based on what checkboxes are left empty by the user...

 

What i have is small application in which a user can add an item to the database and give it tags...

 

for example there is "apple" and it has the tags of "fruit, red, round"

 

What i want is for the user to be able to edit those tags, so the user can remove "fruit" and add "sweet" instead or just remove "fruit" all at the same time.

 

The code i have, somewhat works...

 

This code below loops through the checkboxes and should remove the items that are no longer checked, by going through the database and grabbing all the tags and them checking it against those that are still checked and remove the ones that it didn't find checked...??

 

However whats happening is when i unchecked say "red" it removes all the other items..so if i had "red, fruit, round' and i want to remove "red" it leaves red but removes the rest.

foreach($_POST['tag'] as $r=>$n){
			$t = mysql_real_escape_string($_POST['tag'][$r]);

			$get_tag2 = mysql_query("SELECT * FROM file_cats WHERE fileID='$fileID'") or die(mysql_error());
			while($t2 = mysql_fetch_assoc($get_tag2)){
				$tmp_tag1 = $t2['category'];		

				if($t==$tmp_tag1){
					$remove_tag = mysql_query("DELETE FROM file_cats WHERE fileID='$fileID' AND category='$t' LIMIT 1") or die(mysql_error());	
				}
			}
		}

 

This following piece of code just adds a new tag...however i want it to check to see if that tags already exist in the database, if it does then don't add it just add the new ones..

 

foreach($_POST['tag'] as $k=>$l){
			$tag = mysql_real_escape_string($_POST['tag'][$k]);

			$add_tag = mysql_query("INSERT into file_cats (fileID, category) VALUES('$fileID', '$tag')") or die(mysql_error());	

		}

 

My final problem is that i can't remove items if the second snippet of code is there, i have to remove those lines of code in order to remove items, however i can add items with both loops there.

 

I'm basically stuck and hope that someone here can shed some light on what i'm doing wrong, because i know i'm doing something wrong i just can't find it

 

Anyway thank you in advanced

 

 

[Pikachu2000]

Have you looked at the values in the $_POST array? The values of checkboxes that aren't checked aren't sent in the $_POST array . . .