But how do you make an old version current? Change it's primary key? Nasty. And if you don't do that, you'll have to know which version is live, and that means your queries won't be so simple becuase they'll need to look up which version is live first and won't be able to assume it's a simple key with no appended number. Sounds like a tangle to me. I would go with the two-part key.