| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> RE: Academic ERDs vs. Professional ERDs
Just a guess but some of that may have come out of mathematical set =
theory, sometimes called relational set theory. That at least dates =
back to Venn diagrams.
I have worked with groups that do nothing but data modeling either in = tools like Designer or ERWin. They don't model to define requirements = to be implemented. They data model - period. The biggest difference = that I've seen in those and the "real" ones is an overuse of entity = subtyping. Entities that have eight levels of subtyping are beyond my = comprehension. Maybe it's good that they don't get implemented. Maggie
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 Ryan
Sent: Saturday, February 07, 2004 3:14 PM
To: oracle-l_at_freelists.org
Subject: Re: Academic ERDs vs. Professional ERDs
They are very similiar to class diagrams which are used outside of =
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
> If it is not used outside of academia, then it is either ahead of its =
time
> (due for general adoption) or of absolutely no practical use =
whatsoever.
>
> Given that decision-tree, how long have these concepts been around? =
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 =
relationship
sets.
> > The relations between them seemed very similiar to relations in a =
class
> > diagram.
> > However, I when I look into Erwin and Designer the ERDs there seem =
to be
> > closer to table models. Does anyone use the academic type of ERDs
> > professionally?
> >
> > ----------------------------------------------------------------
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > ----------------------------------------------------------------
> > To unsubscribe send email to: oracle-l-request_at_freelists.org
> > put 'unsubscribe' in the subject line.
> > --
> > Archives are at http://www.freelists.org/archives/oracle-l/
> > FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> > -----------------------------------------------------------------
>
> ----------------------------------------------------------------
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> ----------------------------------------------------------------
> To unsubscribe send email to: oracle-l-request_at_freelists.org
> put 'unsubscribe' in the subject line.
> --
> Archives are at http://www.freelists.org/archives/oracle-l/
> FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> -----------------------------------------------------------------
>
-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Sat Feb 07 2004 - 22:16:57 CST
 |
 |