UML Class Relationships

Question

I would like to confirm whether I am on the right track when identifying common UML class relationships. For example, is the relationship between:

1

Answer 1

The convention that I use to remember which is which is that an composite relationship means that contained instances can't exist without it's enclosing type whereas in an aggregate relationship, objects can exist without the enclosing type As an example:

• A Car 'has' 4.Wheels (aggregation)

• A Cars Vehicle Identity Number is 'part of' a Car (composition)

(Rubbish example, but the best I could bring to mind :)