Company hierarchy class diagram

Question

I want to create an UML class diagram of a company hierarchy and I want to especially to mention that every employee has a superior in the hierarchy (for exemple every department in a company has chief and a chief is a superior of other employees in the departement ). I build this diagram but I feel that there is some thing wrong

Answer 1

I would omit every generalization, it leads to hell (imagine simple situation - you have a hospital with doctors and patients. How many instances of one person will you have, if a doctor brakes his ankle and becomes a patient? And now you decide to have a library. A doctor can borrow a book as well as a patient.). Anyway, I would depict your domain as is at the diagram below (with example).

As for you requirement: I want especially to mention that every employee has a superior in the hierarchy. It is not feasible in a real world. So I use 0..1 multiplicity.

Answer 2

According to your description I'd come up with this:

A Department is composed of Employee s. A Chief is an Employee and there's exactly one Chief per Department .

There are definitely other ways to model this. Especially the generalization might be done in different ways. This depends on lots of domain details which can't be discussed here. But basically you could start with this approach.