Re: Mixing OO and DB

From: Dmitry A. Kazakov <mailbox_at_dmitry-kazakov.de>
Date: Sat, 23 Feb 2008 11:07:21 +0100
Message-ID: <1t8m5ppgq9lf1.1ouk3q6lbb3et.dlg_at_40tude.net>


On Sat, 23 Feb 2008 04:02:34 +0100 (CET), Yagotta B. Kidding wrote:

> "Dmitry A. Kazakov" <mailbox_at_dmitry-kazakov.de> wrote in
> news:1uslk379r2ino$.1scu4stwa18dk$.dlg_at_40tude.net:
>

>> On Fri, 22 Feb 2008 12:57:03 -0800 (PST), JOG wrote:
>> 
>>> Anyone got any ideas how circles 'behave' exactly?
>> 
>> They do such that:
>> 
>> 1. the length of a circle is 2 Pi R
>> 2. the diameter of is the longest chord of
>> 3. the area of is Pi R**2
>> ...
>> 
>> Behavior = set of provable statements about circles.

>
> In the light of my recently discovered lemma, what I am about to say is
> probably pointless, but being in a charitable mood I'll try anyway.
>
> The set of provable statements about the circle is a simple consequence
> of the Eucledean postulates (or their Hilbert's reformulation). As such,
> the provable statements do not add any new information (or "behaviour")
> to what is formulated by the third Postulate.

In which sense information has to be added? To what? To circles? Are they information-additive?

The question was about how circles behave. They do in the only observable in geometry way. That is by proving theorems about them.

> More interestinly though, your definition of behaviour is rather at odds
> with the accepted OOP use of the term as the collection of 'methods' of
> a specific class. Surely, an OOP practitioner should know better than
> that !

Firstly, in case you have missed it, a computational object called "circle" is not a circle.

Secondly, the model of circles based on types will have methods. All these methods, provided, that the model indeed models circles, have implementations based on the provable statements about geometrical circles.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
Received on Sat Feb 23 2008 - 11:07:21 CET

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