Ah, you cite David Hay. He's the best! His new book, Requirements =
Analysis from Business Views to Architecture is excellent!! He shared =
one of his themes, "Making Your Entities Behave: Entity Life Histories" =
in the ODTUG Technical Journal (December, 2002). It's one of his best =
and on the ODTUG web site at www.odtug.com. I hope to hear some of his =
presentations at the ODTUG conference in June.
As an academic exercise, I recall one developer who modeled the =
universe with two entities, "things" and "thing types". After some =
discussion, we realized that "thing types" were actually "things" also. =
Hence, we were down to one entity. Of course it had a recursive =
relationship. And yes, there would be a lot of code to write to make it =
work. :-)
Respectfully,
> Maggie Tompkins - CAD SQA
> Corporate Applications Division
> Technology Services Organization - Kansas City
> Defense Finance and Accounting Service
> 816-926-1117 (DSN 465); Margaret.Tompkins_at_dfas.mil
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Jared Still
Sent: Sunday, February 08, 2004 11:25 AM
To: Oracle-L Freelists
Subject: RE: Academic ERDs vs. Professional ERDs
But of course, there is after all only one data model required;
http://www.tdan.com/i005fe03.htm
Everything else is fluff.
Jared
On Sat, 2004-02-07 at 20:16, TOMPKINS, MARGARET wrote:
> Just a guess but some of that may have come out of mathematical set =
=3D
> theory, sometimes called relational set theory. That at least dates =
=3D
> back to Venn diagrams.
> I have worked with groups that do nothing but data modeling either =
in =3D
> tools like Designer or ERWin. They don't model to define requirements =
=3D
> to be implemented. They data model - period. The biggest difference =
=3D
> that I've seen in those and the "real" ones is an overuse of entity =
=3D
> subtyping. Entities that have eight levels of subtyping are beyond my =
=3D
> comprehension. Maybe it's good that they don't get implemented. =
Maggie
>=20
> Respectfully,
> > Maggie Tompkins - CAD SQA
> > Corporate Applications Division
> > Technology Services Organization - Kansas City
> > Defense Finance and Accounting Service
> > 816-926-1117 (DSN 465); Margaret.Tompkins_at_dfas.mil
>=20
>=20
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Ryan
> Sent: Saturday, February 07, 2004 3:14 PM
> To: oracle-l_at_freelists.org
> Subject: Re: Academic ERDs vs. Professional ERDs
>=20
>=20
> They are very similiar to class diagrams which are used outside of =3D
> academia.
> ----- Original Message -----
> From: "Tim Gorman" <tim_at_sagelogix.com>
> To: <oracle-l_at_freelists.org>
> Sent: Saturday, February 07, 2004 2:55 PM
> Subject: Re: Academic ERDs vs. Professional ERDs
>=20
>=20
> > If it is not used outside of academia, then it is either ahead of =
its =3D
> time
> > (due for general adoption) or of absolutely no practical use =3D
> whatsoever.
> >
> > Given that decision-tree, how long have these concepts been around? =
=3D
> I'm
> > sure the footnotes have dates... :-)
> >
> >
> >
> >
> > on 2/7/04 9:47 AM, Ryan at ryan.gaffuri_at_cox.net wrote:
> >
> > > I'm taking academic database classes and last semester we covered
> academic
> > > ERDs. The material in the book discussed 'entity sets' and =3D
> relationship
> sets.
> > > The relations between them seemed very similiar to relations in a =
=3D
> class
> > > diagram.
> > > However, I when I look into Erwin and Designer the ERDs there seem =
=3D
> to be
> > > closer to table models. Does anyone use the academic type of ERDs
> > > professionally?
> > >
> > > ----------------------------------------------------------------
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>=20
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Received on Sun Feb 08 2004 - 21:10:16 CST
