Re: Lucid statement of the MV vs RM position?
From: Marshall Spight <marshall.spight_at_gmail.com>
Date: 5 May 2006 08:34:42 -0700
Message-ID: <1146843282.012995.233710_at_y43g2000cwc.googlegroups.com>
> No, I think that's right. In the resulting relation, the set of
> attributes that were not grouped, functionally determines the RVA. That
> follows from the definition of GROUP.
Date: 5 May 2006 08:34:42 -0700
Message-ID: <1146843282.012995.233710_at_y43g2000cwc.googlegroups.com>
Jon Heggland wrote:
>
> No, I think that's right. In the resulting relation, the set of
> attributes that were not grouped, functionally determines the RVA. That
> follows from the definition of GROUP.
Isn't GROUP an aggregate operator? And wouldn't the above be true for any aggregate operator? Replace GROUP with SUM, for example.
(I don't know if D&D consider GROUP an aggregate or not, but it certainly meets the definition AFAICT.)
Marshall Received on Fri May 05 2006 - 17:34:42 CEST