Date: Thu, 24 Jul 2008 09:25:39 -0400
"David BL" <davidbl_at_iinet.net.au> wrote in message
> On Jul 24, 10:56 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>> > In a database encoding there is only a single defined interpretation
>> > of the encoded attributes as values in the RM formalism. Therefore
>> > there is no distinction between symbol and value that can be made.
>> I don't agree. Under the domain closure, unique name and closed world
>> assumptions, a database is a proposition that is supposed to be true.
>> the database is physically implemented is irrelevant.
> A relation is formally defined as a set of tuples. Nothing more!
There are several definitions, but that is neither here nor there. Relations were chosen because they look and behave a lot like the extensions of first order predicates. Of course the extension of a predicate includes both positive and negative formulae, but the closed world assumption enables the elimination of the negative formulae. Received on Thu Jul 24 2008 - 15:25:39 CEST