Re: Nulls, integrity, the closed world assumption and events

Cimode wrote:
> David wrote:
> > Consider the following relation
> >
> > person(P,M,F) :- person P has mother M, father F.
> >
> > By induction a non-empty
> > database would have to be infinite.
> A false premise makes all deductions coming from it false. Closed
> World Assumption does not say anything about the number of element that
> belong to a domain of values from which one attribute values are
> derived. In the case of a *person* domain, the number of elements in
> the set is certainly finite. Therefore, the number of propositions
> involving person as an attribute is limited as well.

Would not the question be better stated:

If a table lists linked chains (with the linked-to link), how is the final link (whether first or last) stated?

In such a case i link the item to itself.

B. Received on Mon Jan 08 2007 - 18:11:53 CET