Ryan -
Yes class diagrams and entity relationship diagrams look very similar, and are related, but they aren't the same thing. People in the object oriented world often think of databases as a place to store persistant objects, and if that were true, class diagrams would be all you'd need. But the data that you use as part of one class in one application might be used for an entirely different purpose in another. For instance, I have a Contact application that stores names, addresses, e-mail addresses and phone numbers. But another application reads the contact database to find out where to send notices of significant system activity. The contacts are related to the work via the roles each contact has in the other application. Try putting THAT in a class diagram. We actually need both ERDs and CDs and maybe a database behind them to show how entities are mapped to classes.
-----Original Message-----
From: Ryan [mailto:ryan.gaffuri_at_cox.net]
Sent: Sat 2/7/2004 11:47 AM
To: oracle-l_at_freelists.org
Cc:
Subject: Academic ERDs vs. Professional ERDs
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?
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Received on Tue Feb 10 2004 - 08:59:29 CST
