Which normal form is this violating?

From: Roger Redford <dba_222_at_yahoo.com>
Date: 24 Apr 2002 21:31:04 -0700
Message-ID: <a8c29269.0204242031.9d9964f@posting.google.com>

Hello DB Design experts,

I'm having the usual disputes about database design issues.

The information that my coworkers have is say, x and y. It has a one to one relationship. Therefore, it goes into one and the same table.

Table_A
Fieldx (pk)
Fieldy

However, they are arguing that it goes into another table.

Table_A
Fieldx (pk)

Table_B
Fieldx (pk)
Fieldy (not null)

(Actually, thye have "designed" a number of strange tables, and then put views on top of them, to come back to the same one to one relationship. Very strange and complex. )

What normal form does this violate? It isn't 1st, 2nd, or 3rd. Boyce-Codd maybe? The crazy thing about the design texts, is that they rarely cover mistakes in design. This is a common one.

Thanks Received on Wed Apr 24 2002 - 23:31:04 CDT