Newbie question about db normalization theory: redundant keys OK?

With a few hours of theory under my belt, I'd like to ask if there's ever a time that you don't want a completely normalized dB, that is, a normalized database being a dB that has no redundant information (my understanding of what a normalized database is).

Or, is there ever a time that you want redundant keys (that is, the same keys in many different tables, that obviously are not linked (in a relationship) between two tables?). Having redundant attributes and/ or keys seems to me a very lazy way of designing a database that doesn't require lots of initial thought, but of course you have to pay for it by meticulously "synching" all redundant keys to one another everytime there is a change in one of the redundant keys, so the keys don't drift and have different values.

But is there ever a time you want to do this?

THanks in advance

RL Received on Wed Dec 12 2007 - 16:26:36 CST