Re: Lucid statement of the MV vs RM position?

From: Jon Heggland <jon.heggland_at_idi.ntnu.no>
Date: Thu, 04 May 2006 17:48:31 +0200
Message-ID: <e3d7oe$6lt$1@orkan.itea.ntnu.no>

Bob Badour wrote:

> Marshall Spight wrote:

>> I have no idea what GUNF is, and it's not clear from context. Further,
>> a Google search for "gunf" or "gunf darwen" produced no useful
>> information.
>>
>> What am I missing? Anyone have any further pointers to useful reading?
>
> It's just a guess, but I figured it stood for "Group/Ungroup" normal form.

Yes. I don't think it has spread beyond the thethirdmanifesto mailing list yet; Darwen presented it a little over a month ago. He writes:

"Let rv be a relvar with an attribute rva that is of a relation type with attributes a1, ..., an. Then rv is in GUNF if and only if there exists a possible value r of rv such that there does not exist a relation s such that:

r WHERE COUNT(rva) > 0 = s GROUP ( { a1, .., an } AS rva )"

-- 
Jon

Received on Thu May 04 2006 - 10:48:31 CDT