Two- way Associations(双向关联) a two-way association indicates bi-directional navigation between objects of two classes 双向关联中每个类都有另外一个类的对象的引用 Course Student courses students 1818 Two-way Associations(双向关联) • A two-way association indicates bi-directional navigation between objects of two classes. – 双向关联中每个类都有另外一个类的对象的引用。 Course Student -courses -students