Re: Sixth normal form
Date: Tue, 21 Aug 2007 12:31:27 -0000
Message-ID: <1187699487.121719.181130_at_g4g2000hsf.googlegroups.com>
On 21 aug, 05:52, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>
> My argument is that if there is a functional relationship from one set of
> attributes to another in a less normalized schema, then there should still
> be a functional relationship after decomposition.
This cannot be your argument because it is only a reformulation of your claim. You still have yet to supply any form of argumentation that justifies that claim.
You seemed to come close to such a thing by invoking the domain closure property and the principle that you don't want to change the upper and lowerbounds of the relationships between the objects in the domains, but now you start special pleading because you only want to apply those principles for the lower and upper bounds in the direction of the FDs, i.e., you are only applying the principles there where you need them to support your claim and ignore them where they contradict your claim. This way you are of course proving precisely nothing.
Since I don't see any progress, and suspect that there will none in the near future, I'm signing off from this discussion.
- Jan Hidders