Question

So, I have an enumeration that is as follows:

+---------+
|TypeCours|
|  Enum   |
+---------+
| TD      |
| TP      |
| CM      |
+---------+

and for another class (Module), I need to modelize the fact that for each of those enum values, I require an int value.

So that every instance of Module has for example (TD, 15), (CM, 30) and (TP, 40) to its disposal. Where 15, 30 and 40 are specific to the instance.

I’ve been advised to use an enum since it should allow easier evolution (like adding a value to the enum type) compared to just having 3 int fields doing the same job.

My question is, what kind of association do I need between my class Module, the enum TypeCours (and potentially a third class?) to modelize that need ?

Answer 1

Interesting questions. I would create a new class called TypeCoursValue which has the value of TypeCourse and the int value. Then you must add a relation between Module and TypeCoursValue.

The interesting part is how to model the constraint that specifies that for every value of TypeCours you need an instance of this new class. I don’t know of any UML notation to do this other than comments, so I would add a comment to the relation “there must be one instance of TypeCroursValue for every value of TypeCourse“.