n-ary association class

[confucius]

Hello all,

How can I define graphically an association class for an n-ary association ? The dotted line is expected to connect the association class to the diamond shape representing the n-ary association. Even how hard I try ( ) the source and destination ends of the dotted line still continue to connect the association class (correct) to one of the link between the diamond and one of the classes participating in the n-ary association, which is incorrect.  

thanx.

[Paolo F Cantoni]

Can you post a diagram fragment to illustrate your problem?

Paolo

[confucius]

Paolo,

An example of what I am trying to do is at http://www.jot.fm/issues/issue_2006_07/article5 (figure 1(a)) (the Supply association class describing the 3-ary association between Vendor, Project and Part).

thanx.

[Jan ´Bary´ Glas]

Hi confucius,
I know that it makes another self-association on the diamond-association with the associated class.

Does not look exactly like your picture, but the meaning is clear.
See picture.

[confucius]

Hi Jan,

That's a good hack, event if not UML compliant  :-/ I had expected EA to be more "friendly" on that one.

thanx.

[Eve]

As far as the visual goes, try a dependency with unspecified direction.

[KP]

Whatever you decide won't affect code generation, so you're free to choose whatever notation you like best. I would simply attach the class to one of the association connectors in the normal manner.

[Paolo F Cantoni]

If you search for the term n-ary (posted by PaoloFCantoni) you'll see a contrary view on how to represent the n-ary relation - to that represented in the JOT article (which I think looks, superfically, clumsy).

(I'll read the article more closely and provide a more formal response).

In particular the diagram in the article: [size=13]Navigability[/size] illustrates my thoughts.

Other entries (found by the search) will also show how to use Inversion of Control (IOC) to implement the n-ary Association so represented in code.

HTH,
Paolo