Re: more closed-world chatter

On 3 mai, 17:26, "David Cressey" <cresse..._at_verizon.net> wrote:
> "Cimode" <cim..._at_hotmail.com> wrote in message
>
> news:1178200219.598399.84110_at_o5g2000hsb.googlegroups.com...
>
>
>
> > On May 2, 10:13 pm, paul c <toledobythe..._at_oohay.ac> wrote:
>
> > > If I have a domain of items consisting of the values "a" and "b" and a
> > > domain of item prices consisting of the values "1" and "2" and an empty
> > > relation {ItemID, Price} known by the relvar name "Items", I take it
> > > that the logical complement of "Items" has four tuples - loosely,
> > > <a,1>,<a,2>,<b,1>,<b,2>.
>
> > > If I select from Items where Price = 3, should a dbms answer with an
> > > empty relation or should it take exception, such as "illegal question"?
> > I would like to point out two comments triggered by your question.
>
> > A TRDBMS should detect disjoint types are to be determined at compile
> > time. In my perspective, there should be no exception because there
> > should be no execution in the first place. That of course, in a
> > purely empirical perspective.
>
> I am not convinced. Why should the binding happen at compile time.
I apologize. I should have been more explicit in my statements

Because a TRDBMS separating the logical and physical layer should somehow beware of the *state of disjointness* intervals/sets priorily to constructing user view (such information could perfectly be stored), then it is not unreasonnable to assume that such information could be available before starting the process of user view building. If one considers the building of the user view as the executing part of the process then , by analogy, the previous part should be the compiling/binding part. (In a TRDBMS, both would be in fact the same such as the what we saw in Transrelational model).

Hope this clarified.

> Couldn't a TRDBMS be extended to allow dynamic typing?
In a sense Received on Thu May 03 2007 - 18:42:29 CEST