Q
Problem solve Get help with specific problems with your technologies, process and projects.

Cycle relationships in ER diagram?

I have this ER diagram, which supposedly has two cycle relationships. I have doubts because one person says that it is indeed cycle relationships, and another person says that it does not. The diagram can be found at: http://www.jmontalvo.com/registrations1000x900.jpg.

You diagram is really hard to read on a 160 by 160 display, but the only circular reference I can see (where an entity contains its own Primary Key as a Foreign Key too) is AppUser. You could create a true circular reference there.

A cycle relationship is more complex, where some group of entities refer to each other in such a way that it is possible to create a "loop" of relationships that feed back into itself. There are several possible 1:N relationships that could generate a cycle, but I can't see how they would naturally assume a cycle.

The short answer is yes, a cycle is possible in more than one way, but I don't see how it would occur naturally.

For More Information

This was last published in September 2003

Dig Deeper on Oracle database design and architecture

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

SearchDataManagement

SearchBusinessAnalytics

SearchSAP

SearchSQLServer

TheServerSide.com

SearchDataCenter

SearchContentManagement

SearchHRSoftware

Close