I'm currently taking a class for database design, and we're using the ER diagram style designed by Peter Chen. I have a couple of problems with this style:
- Keys in relationships don't seem realistic. In practice, synthetic keys like "orderid" seem to be used in almost all tables, including association tables, but the Chen style diagrams heavily favor (table1key, table2key) compound keys.
- There is no notation for datatype.
- The diamond shape for associations is horrible, and produces a cluttered diagram.
In general, it just seems hard to capture some relationships with the Chen system.
What ERD style, if any, do you use? What has been the most popular in your workplaces? What tools have you used, or do you use, to create these diagrams?