Re: Proposal: 6NF

From: vc <boston103_at_hotmail.com>
Date: 14 Oct 2006 14:47:55 -0700
Message-ID: <1160862475.439128.144340@m73g2000cwd.googlegroups.com>

David Cressey wrote:
> "vc" <boston103_at_hotmail.com> wrote in message
> news:1160752928.197097.241340_at_m73g2000cwd.googlegroups.com...
>
>
> > RIght, but my understanding of the OOP stuff leads me to believe that
> > a subtype should '"inherit" its type operations. If so, assuming R is
> > our base type, what do we do about division in Z (regarded as an R
> > subtype) ;) ?
>
> My understanding is that a subtype inherits type operations unless
> overridden or forbidden.
>
> Also, are we really talking "subtype" or are we talking "subset"?

That's exactly what I consider strange in trying to equate subtype with subset (as Cardelli does). An OOP person expectation would be that a subtype would "inherits type operations" which does not happen in the simple R to Z example. Received on Sat Oct 14 2006 - 16:47:55 CDT