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Re: What databases have taught me

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Wed, 28 Jun 2006 23:38:57 +0200
Message-ID: <44a2f66d$0$31652$e4fe514c@news.xs4all.nl>


Frans Bouma wrote:
> mAsterdam wrote:
>

>>Frans Bouma wrote:
>>[snip]
>>>	Funny thing is that if you give 3 randomly chosen database
>>>architects (or whatever the f... some people want to call these
>>>people) the task to develop the RDM for a big hospital (so you end
>>>up with at least 700 or so tables), you will definitely get 3
>>>completely different models.
>>
>>Is this from experience - did you see 3 actual models for
>>a big hospital? Did you try to find out what was same,
>>similar and different? I speculate that it is speculation.

>
> I have, actually. All 3 had over 1000 tables. Not for the same
> hospital, but all were databases for the information systems for big
> hospitals. It struck me that they were so different. Of course they all
> define 'patient' but it was kind of odd that they ended up with such
> different models. And yet, when you looked at them they all made sense.

What would you do if these three hospitals merged into one?

>>It does not match my experience. I did some admittedly
>>shallow comparisons of different data models in operation
>>for different organizations in the same businesses
>>(not hospitals). The similarities were striking,
>>noted differences were accounted for.
>>I think this is because when you are in the same
>>business, you have to deal with the same
>>facts. If you don't you are in a niche.

>
> Then our experiences differ indeed. :)
Yes. I'd still prefer some research.

You don't? (snippage)

> My example was more to illustrate that if you talk about something
> like 'RM' the end result of the analysis phases might be a RDM, and it
> also might be following all the rules defined for RM, but semantically,
> does it make sense, is it 'correct' when you project it on reality?
> That's something that's unclear, which is the same with OOAD and which
> was IMHO the reason why it was more or less classified as not useful by
> some, while RM and OOAD are actually in the same boat: the end result
> can be tested technically if they obey the rules of RM resp. OOAD, but
> if they are 'correct' with respect to reality is not clear in both
> situations as in: not for 100% certain. (otherwise no software project
> would ever fail ;))

The accuracy of the models gets tested in production.

-- 
"The person who says it cannot be done
should not interrupt the person doing it."
Chinese Proverb.
Received on Wed Jun 28 2006 - 16:38:57 CDT

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