Do link tables need a meaningless primary key field?

Question

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

Answer 1

I (almost) always use the additional single-column primary key. This generally makes it easier to build user interfaces, because when a user selects that particular linking entity I can identify with a single integer value rather than having to create and then parse compound identifiers.