Many-to-many relationship in oop

Question

what is best way to model many-to-many relationship?

lets say we have a two classes , Team and Player

• any given P

Answer 1

It's worth to distinguish the API feel from actual implementation.

While it makes sense for both classes to expose such a collection (e.g. get*List()), they don't neccessarily have to hold the instance of the collection.

I suggest you create a League class or something alike, that holds some sort of a private player-team mappings dictionary. Additions to those 'collections' thorough the Team/Player instance, should call internal methods on the League instance to update the mappings. This way, you keep updates atomic (as Andrey suggested) and error free.