Here's the easiest way I can think of to explain this. Imagine a user wants to bookmark a bunch of webpages. There's a url table with a UrlID and the actual url. I'd like the user to have a list of UrlIDs which are unique (but I don't need the constraint) and a 32bit int value such as an epoch date. The only two things I care about is 1) being to check if UrlID is in this list or not and 2) get the entire list and sort it by date (or second value)

If it helps I'm expecting no more than 8K bookmarks but most likely it will be <128