I am working on a couple of link tables and I got to thinking (Danger Will Robinson, Danger) what are the possible structures of a link table and what are their pro\'s and c
i've used both, the only benefit of using the first model (with uid) is that you can transport the identifier around as a number, whereas in some cases you would have to do some string concatenation with the composite key to transport it around.
i agree that not indexing the foreign keys is a bad idea whichever way you go.