Resequencing logic

I apologize if this message is a repeat; I've had trouble posting with Thunderbird. I'm interested in how you folks would approach the following issue: You have a list of data, in a user-defined sequence. For instance, a list of song titles that can be rearranged on a web page in any order. I don't think I have the best grasp of the logic involved, and as such, the problem is a real pain for me. I use this approach: -If adding, records after or equal to the new (requested) spot are incremented -If moving up, records before the current spot and after or equal to the new spot are incremented -If moving down, records after the current spot and before or equal to the new spot are decremented -If deleting, records after or equal to the current spot are decremented Is there some MySQL or PHP function that will handle this sort of reordering business, or is there possibly a simpler logic I could use? Thanks, Matt mgrimm@healthtvchannel.org