Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

From: David Cressey <cressey73_at_verizon.net>
Date: Thu, 03 May 2007 16:45:42 GMT
Message-ID: <Wko_h.6617$r77.5046_at_trndny08>


"Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message news:4639fde8$0$4017$9a566e8b_at_news.aliant.net...
> David Cressey wrote:
>
> > "Brian Selzer" <brian_at_selzer-software.com> wrote in message
> > news:VBk_h.20774$Um6.2594_at_newssvr12.news.prodigy.net...
> >
> >>"David Cressey" <cressey73_at_verizon.net> wrote in message
> >>news:6ui_h.5979$YW4.662_at_trndny06...
> >>
> >>>"Cimode" <cimode_at_hotmail.com> wrote in message
> >>>news:1178174344.866049.272810_at_h2g2000hsg.googlegroups.com...
> >>>
> >>>>On 2 mai, 21:47, paul c <toledobythe..._at_oohay.ac> wrote:
> >>>>
> >>>>>Cimode wrote:
> >>>>>
> >>>>>...
> >>>>>
> >>>>>
> >>>>>>Brian,
> >>>>>
> >>>>>>Don't you think you are overcomplicating things?
> >>>>>
> >>>>>I certainly do. RT isn't as complicated or subtle as this thread is
> >>>>>making it out to be.
> >>>>
> >>>>I was not thinking about *subtleness*. I am having trouble following
> >>>>Brian's wordy line of thought. I am not sure he and I have do not
> >>>>have the same perception of what logical and physical independence
> >>>>is. I was also refering to terms I am not familiar with such as
> >>>>*database state*. To me they are totally foreign to RM formal
> >>>>theory.
> >>>>
> >>>>Maybe you could clarify. Thanks.
> >>>>Regards...
> >>>>
> >>>>[Snipped]
> >>>
> >>>
> >>>I think that "state" is a fundamental concept in computing. As such,
> >>>Brian
> >>>and others ought to be able to use it to communicate rather precisely,
> >>>without needing to present a formal definition. If you know what a
> >>>"database" is and you know what a "state" is, I think you know what a
> >>>"database state" is.
> >>>
> >>>Having said that, I'll admit that I'm often lost by Brian's argument.
> >
> > He
> >
> >>>seems to be arguing that transaction atomicity is an undesirable
feature
> >>>of
> >>>our data model. If I'm reading that right, I abandon the effort to
> >>>understand the rest of what he's saying.
> >>>
> >>
> >>I'm not sure which argument you're referring to. Several have arisen.
> >
> > I'll
> >
> >>try to state them consisely:
> >>
> >>1. assignment is bad: it breaks one of Codd's rules, unless you use
> >>surrogates, which breaks another of Codd's rules. Use a set of inserts,
> >>updates, and deletes instead.
> >
> > I'll agree up to a point. I don't agree that "assignment is bad". I
will
> > agree that
> > assignment is not a substitute for inserts, updates, and deletes.
>
> It's all well and good that the two of you agree. I don't agree with
> either of you.
>
What part of what I said don't you agree with?

>
> >>2. multiple self-joins are bad for performance: use a cursor to
eliminate
> >>them and thus improve performance.
> >
> > It depends. Cursors are not the entire algorithm. The process that
uses
> > the cursor output can (and frequently does) burn more resources than
the
> > extra reads occasioned by a declarative approach. This depends on the
> > computing/DBMS environment one uses.
>
> I see no reason to cede the point he made. I have found optimizers far
> better at optimizing self-joins than most programmers are.
>

Maybe I cut him too much slack. If the past is any guide, optimizers will get better, and Brian won't. It's instructive that Both Cimode and Kevin provide actual data, while Brian merely states his claim.

But even if he wins this particular race, he will not convince me that cursors are the way to go. I've seen too much evidence to the contrary.

>
> >>3. in a closed world, there is no such thing as "missing information."
> >
> > In the real world, databases are often an imperfect image of the real
world
> > they are supposed to represent. surely you wouldn't argue that a real
world
> > database would be of no value if it were missing one row in a table
that
> > intended to follow the closed world assumption.
> >
> > It's the classic, "we can't admit you as a patient, because you aren't
in
> > the database" syndrome. Bad, but you live with it until you can
correct
> > it.
> >
> > If you are building stuff for the real world, you by golly have to do
> > something intelligent with "missing information".
>
> One has to do something intelligent with the information one has, and
> one has to allow someone intelligent to deal with the information one
> doesn't have. I don't see how you arrive at your destination.

I should have said "one has to do something intelligent" rather than "you". The impersonal "you" is part of my dialect, even though I prefer the British "one". I'm not sure what my destination was. I merely wanted to question the reality of a world where there is no missing information. Received on Thu May 03 2007 - 18:45:42 CEST

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