Re: ID field as logical address
Date: Tue, 2 Jun 2009 18:16:59 -0700 (PDT)
On Jun 2, 10:26 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> David BL wrote:
> > On May 31, 10:20 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> >> one of the many other confusions I snipped is that assignment is part of
> >> relational theory, whereas it's not, it is a concept certain kinds of
> >> languages need.
> > If by "relational theory" you mean the relational algebra then it's
> > true it doesn't include assignment. But obviously the sub-topic
> > concerns the changes to a relational /database/ over time.
> > This news group by definition concerns database theory. The main
> > purpose of a database is to record values in variables. Whenever a
> > variable is changed it has by definition been assigned with a
> > different value.
> > I doubt you'll take my word for, but perhaps you'll listen to Bob. The
> > following quote comes from a post by Bob in Oct 2003:
> > All D's are imperative. Imperative languages comprise
> > those languages that operate by changing the state of
> > variables. Since a database is a variable, imperative
> > languages are entirely appropriate for data management.
> > Regardless whether one writes expressions using the
> > calculus or the algebra, one manages the data by
> > changing the state of the database variable.
> If you're trying to say RT allows languages that support pointers, okay.
> If you're trying to say RT requires an imperative style, eg.,
> languages that support pointers, you're wrong.
> Just because db values vary
> doesn't mean one must implement variables and assignment.
[snip] Received on Wed Jun 03 2009 - 03:16:59 CEST