Let's see if we can reconcile this. Here is the def. I have:

"An entity is said to be in the BCNF if it is in the 3rd. NF and every data item on which some other item is fully functionally dependent is a candidate key."

I see that the BCNF is an extention of the 3rd. NF. The question arises as to whether the extension applies. Not all tables in the 3rd. NF need/should be extended to the BCNF.

I agree with what you state below with respect to what the BCNF is. My issue is rests with whether the BCNF applies or not. IMO, unless you have the scenario I put forth in my previous post to you, the BCNF does not apply.

That said, while we agree (I think) on what the BCNF is, I think we disagree on the circumstance in which the BCNF applies.

I look at the BCNF as the third and a half NF..< bg >..


< jvp >


>John,
>
>Nope, BCNF simply says that once a table is in 3rd NF for the PK it must also be in 3rd NF for all other candidate keys.