@louis well, what would you select on? If it's not your PK, then not having it makes no difference, and you can still have indices (on timestamp for example, or anything you'll commonly search/order by, but careful with write heavy tables) to filter on (and update/delete), or for a log, full text search might be an interesting thing to enable. PK makes sense for relational data, here you don't seem to treat it as such, and i don't see what you lose for not having it.