Re: Relation subset operators
From: Tegiri Nenashi <TegiriNenashi_at_gmail.com>
Date: Thu, 4 Jun 2009 13:03:58 -0700 (PDT)
Message-ID: <ba65eedb-d297-470d-b4fe-350205da3cb3_at_f16g2000vbf.googlegroups.com>
Date: Thu, 4 Jun 2009 13:03:58 -0700 (PDT)
Message-ID: <ba65eedb-d297-470d-b4fe-350205da3cb3_at_f16g2000vbf.googlegroups.com>
On Jun 4, 2:09 am, cim..._at_hotmail.com wrote:
> <<In a way this is a dual requirement to having two argument of the
> same type! >>
> I do not recall reading this but I have hard time understanding the
> need for such limitation. What prevents performing an agrregate or
> set operation between a relation type and a relation subtype (the
> subtype using the type as a domain of possible values) ?.
Why do you bring in relation subtype (and what is it, actually)? Received on Thu Jun 04 2009 - 22:03:58 CEST