Re: Simple database design question
Date: Tue, 30 Sep 2008 20:56:40 -0700 (PDT)
Message-ID: <f1126964-f1a2-4eac-be38-d1a94f0191e8_at_j22g2000hsf.googlegroups.com>
On Oct 1, 8:40 am, JOG <j..._at_cs.nott.ac.uk> wrote:
> On Sep 30, 4:07 pm, "Mark S. (UK)" <ma..._at_nospamhere.com> wrote:
>
> > Hi all,
> > I have 2 tables, "sims" (as in mobile phone sim cards) and "phones" (as
> > in mobile phones). I can add any number of sim cards to the "sims"
> > table and any number of mobile phones to the "phones" table. Simple enough.
>
> Here you have described two unary predicates: "exists_sim(sim)" and
> "exists_phone(phone)".
Just a rather off topic comment... One time on this ng I discussed a unary predicate like this that stated that such and such exists, and was beaten over the head for being metaphysical. However I don’t think there is anything wrong with using the term "exists" as long as it is understood that the external predicate is in fact something more specific – such as
exists_phone(P) :- phone P was manufactured by Acme Corporation. Received on Wed Oct 01 2008 - 05:56:40 CEST