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Re: Has E/R had a negative impact on db?

From: David Cressey <dcressey_at_verizon.net>
Date: Sun, 23 Apr 2006 12:27:15 GMT
Message-ID: <DoK2g.2291$Cc.1748@trndny07>

"JOG" <jog_at_cs.nott.ac.uk> wrote in message news:1145759385.737434.153510_at_t31g2000cwb.googlegroups.com...
> Neo wrote:
> > > Just a thought. I don't like entities. In fact I despise entities, as
the enemy of good
> > information philosophy.
> >
> > What is your definition of an entity? What steps would one go through
> > to verify something is an entity?
>
> I refer to them as they are specified by Chen. I've already pointed out
> I believe their specification is impossible above simply being
> arbitrary so your second question makes no sense to me.
>

I honestly believe that this long discussion has lost sight of the idea that the E/R model is an analysis model, and not a design model. Arbitrary choices made during the analysis phase can be useful, in order to come up with a conceptual model that is easily communicated from one person to another. That's the main usefulness of an E/R model, IMO. If the E/R model were a design model, then arbitrary choices would be far more costly.

Arbitrary choices during the design phase can (will) come back to bite you if those choices were only arbitrary in your mind, and not in terms of the downstream consequences of the design choice.

Many of the complaints made against undereducated database designers can be grouped into the following class of complaints: the undereducated will often think that a design choice is arbitrary when a more educated person will be able to see different consequences in the various alternatives. Received on Sun Apr 23 2006 - 07:27:15 CDT

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