Re: Impossible Database Design?
Date: Sat, 20 May 2006 01:14:40 +0200
Message-ID: <446e50ad$0$31640$e4fe514c_at_news.xs4all.nl>
-CELKO- wrote:
>>>There is no smallest or biggest number. Most representations do have them. Very similar, no? <<
>
> But his ënd of time" is part of the *model* and not the
> implementation.
Well, yes. As far as as I understand it, they (DD&L) discuss a discrete (vs continuus) universe representation - at least as far as time is concerned. Why the 'but'?
>>>MV resticted to sets. The representation does not immediately show that, though. <<
>
> But Date's [p1: p5] notation requires that there must exist {p1, p2,
> p3, p4, p5} and that they can be ordered by their names. That does not
> make any sense.
I'm not sure if I am getting this the way you mean it. You mean p1, p2 etc. as time points?
I am guessing here:
Something like (whatever it may mean - you could maybe
provide a sensible interpretation?) this:
During Birds
[p1:p5] pink lawn flamingoes
?
> If I discontinue p3 (pink lawn flamingoes) what
> happens to [p1:p5]?
During Birds
[p1:p2] pink lawn flamingoes
[p4:p5] pink lawn flamingoes
> If I replace p3 with p3.1 (yellow lawn flamingoes,
> which are popular here in Austin, TX because of Lance Armstrong), what
> to [p1:p5]?
No p3.1, just:
During Birds
[p1:p2] pink lawn flamingoes [p3:p3] yellow lawn flamingoes [p4:p5] pink lawn flamingoes
> If I replace the "p#" with a UPC code, what to [p1:p5]?
I'm still wondering wether my interpretation of your questions is correct.
> A countable set is not like a time continuum.
> I cannot remove Tuesday
> from the interval [Monday : Thursday].
Not as such, removing Tuesday from an interval over cyclic weekday points renders two weekday intervals.
[Monday:Monday] ...
[Wednesday:Thursday] ...
> I cannot add 'Floobday" to the week. Etc.
Heh - it would become a strange week indeed.
ISTM that's the only reason why I wouldn't add such a day - or are you suggesting there is some reason why, with the ideas of the academics you mentioned it /is/ possible to add "Floobday" to the week, while with DD&L's timepoints it isn't possible, and somehow this makes the academics' approach better?! Received on Sat May 20 2006 - 01:14:40 CEST