Show/copy relationships

[thomaskilian]

Imagine you have a couple of diagrams with one element appearing in more than one of them. Now you may have relations used in diagram A but not in B. If you later want to explicitely show a diagram for this specific class you can create a new diagram and insert the element with all the relations it has. Does that make sense to you?

[sl@sh]

Yes it does - for a class. I thought we were discussing instances?

I did consider this, but for instances I really don't know why anyone would want to do this. For a class, yes that makes sense, and that's what I thought one of the applications of the function.

For an instance however - why would I want to design a diagram just for the purpose of showing a single instance's relations when I could just show the class' relations instead? Yes, this would possibly include some relations that certain instances would not make use of, but deleting connections (or hiding them, rather) - if you really don't want to model that particular relationship - can be done much faster than redrawing exactly the same associations over and over again.

Moreover, the need to recreate associations on instances is vastly error prone - you can easily choose the wrong type of association, give it a different name (so you don't any longer see the actual connection to the relations shown on the class diagram), or simply create associations that don't exist on the class (yet), meaning you don't get proper dependencies when generating the code.

The decoupling of class associations from instance associations is rather awkward, to say the least.

[thomaskilian]

Maybe it's because Insert Related Elements works for all elements - even those where it does not make much sense, like instances.

[JohnWSaundersIII]

At the very least, there should be a way to create links based on the associations, so I don't wind up creating the wrong kind. Perhaps a dialog showing me a list of associations from the classifier of the selected element, and allowing me to check whether to create links. It might also allow me to specify, for an association with a target multiplicity > 1, to create "n" objects and links to them.

Obviously, I haven't thought this through in detail. A moment's reflection suggests EA would want to do something about constraints, ordering, etc. But in the meantime, I'd at least have some correspondence between the links and associations.

And perhaps even a <<trace>> relationship from the association to the link(s)?

John

[Paolo F Cantoni]

"...And a partridge in a pear tree" too, please  

Paolo