Re: Peter Chen and Charles Bachman

From: Leandro Guimarães Faria Corsetti Dutra <leandro_at_dutra.fastmail.fm>
Date: Wed, 05 May 2004 18:34:17 -0300
Message-ID: <pan.2004.05.05.21.34.17.793912@dutra.fastmail.fm>

Em Wed, 05 May 2004 14:25:07 -0700, Gene Wirchenko escreveu:

>>	An ERD is a diagram.  A draft.  For presentation.  Nothing
>>more.


> 

>      Bah!  You think I am going to go to the trouble of drawing

> something useless? If I have an ERD, I use it to develop the database
> schema.

Yet it is just a draft. Incomplete and misleading.

>>	So it is not a logical model.  At most a conceptual one, and
>>incomplete at that.


> 

>      Nope.  It can be a logical model, if done to a RW amount of

> detail. It is not the physical model though.

Physical is totally another story.

ERDs can't represent the constraints of the logical model.

-- 
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Received on Wed May 05 2004 - 16:34:17 CDT