How to avoid circular association (Class Diagram)

Question

I have a Project class that has one Objective. an Objective that has many Projects. a Meeting that can be associated to a Project (which has an Objective) or Objective. How can I represent this relationship in a Class Diagram

I know it shouldn't be done this way

Answer 1

There is absolutely no problem in UML with circular associations. This is common business as soon as you model real life domains. You could even have self-associating classes in a circular association, and it still wouldn't be an issue.

Your only modelling challenge is to represent accurately:

A Meeting that can be associated to a Project (which has an Objective) or Objective.

You must therefore first disambiguate:

• can it be none of the two (your diagram gets it) ?
• can it be both? If yes:
  • can the meeting's objective be different from the project objective (your diagram still gets it) ?
  • or shall objectives of the meeting and the project be aligned (see my other answer here, how to express constraints between direct and indirect associated classes using OCL)
• must it be the one or the other but not both (see this question for the best recent answers on this topic)?