Re: Evolution of Date's "Abstract Machine" (via CM)

"Alfredo Novoa" <alfredo_novoa_at_hotmail.com> wrote in message news:fbtd91lpe59e8r2pd8p6ijssebdhhopi8r_at_4ax.com...
> On Fri, 27 May 2005 03:37:33 GMT, "mountain man"
> <hobbit_at_southern_seaweed.com.op> wrote:

"mountain man" <hobbit_at_southern_seaweed.com.op> wrote in message news:1Cwle.2325$BR4.1097_at_news-server.bigpond.net.au...

> Date classically depicts a "data model" as an "abstract machine"
> which is comprised of "abstract, self-contained, logical definition
> of the data structures, data operators, and so forth".
>
> He then distinguishes the model from its "implementation", defining
> this to be a "physical realisation on a real machine of the abstract
> machine".
>
> It appears to me that Date's "abstract machine" is referenced at
> two separate processes within the prefessional environment of
> database systems, the first being at the commissioning of the
> implementation (in the design process perhaps), and the second
> being during the process of change management --- over the
> years that follow.
>
> In the second process, due to changes in the environment, new
> functionality is required, new data structures may be needed,
> new relationships evoked, new rules created, or old rules changed.
>
> Obviously, the "abstract machine" is consulted at these points
> and stages, and is itself evolved with respect to its previous
> "implementation". IOW, subsequent design work will always
> be required due to the standard considerations incumbent with
> change, and the reference point for this subsequent design, is
> the original design of the "abstract machine".
>
> Summarising, theory is just as important, and indeed can be
> just as critical, in change management as it is at initial design,
> and effectively, the "abstract machine" is not a static thing
> but is continually evolved through use.
>
>
> And in this manner may database systems theory be
> optimally associated with practice. But nowhere can
> I find Date saying this, and hence these two questions:
>
> 1) Is it clear/true that Date's "abstract machine" necessarily
> evolves due to change management considerations over
> time?
>
> 2) Does Date reference this issue?
>
>
>
> Thanks for any comments,

> Please, keep your mental masturbation in private.

Let me make a revision to that last comment of mine. Thanks for any constructive comments.

I believe the subject matter for discussion in this forum is database theory, but I could be mistaken.

Pete Brown
Falls Creek
Oz
www.mountainman.com.au Received on Sat May 28 2005 - 05:30:53 CEST