Diagram correction needed.

[IanS]

Hi,

was just browsing through the on-line help and found the class diagram on this page.

http://www.sparxsystems.com/resources/uml2_tutorial/uml2_classdiagram.html

I know it's only an example, but I would be surprised in real life if anyone would use a composite aggregation between the classes Contact Group and Contact. It should just be a normal aggregation. It makes sense between AddressBook and Contact, but not between the others. Also the parent/child relationship between ContactGroups is unlikely to be a composite aggregate, just a normal aggregate.

It is even contradicted further down the page under the subsection Aggregation.

Thought someone might want to improve that.

cheers

IanS

[IanS]

Further down on the page, I would also be surprised if the relationship between Employee and Project is directional. It is very common for people to be working on more than one project.

[RoyC]

Thanks for your comment.

I think that the online Help reflects your suggestion:

http://www.sparxsystems.com.au/EAUserGuide/index.html?classdiagram.htm

I have asked for the Resources webpage you identified to be updated to incorporate the Help page diagram. This might not happen immediately though.

For your second point, I think that the paragraph just above the diagram makes exactly that point, and the diagram represents the global statement that Employees work on Projects, and have Roles on those Projects. You could have a multiplicity on the relationship, but it isn't absolutely necessary. You would represent a more specific case with instances of the Classes - Employee John is a Project Manager on Project Falcon, and a Lead Analyst on Project Condor. Is that correct?