>As I said in my reply to , if there is more than one candidate for the primary key then the Boyce-Codd NF applies. It says that once a table is in 3rd NF for the chosen PK it must also be in 3rd NF for all feasible alternate keys.
Thanks for your answer. Excuse me if I'm a bit slow on this, but I can't recall a practical example of this. Why should I have to normalize (3NF) all alternates having did it with the PK?
