How to model an association class in a UML class diagram where only one of the class has access to it?

Question

Given this scenario: "Clinicians can record their own notes for each patient, viewable only by them." I would model it like this:

Clinician ----> Patient

and "Notes" as an association class between clinician and patient. However, does this mean that the "Notes" class is viewable by both clinicians and patients? If so, how do I indicate that Notes can only be viewed by clinician?

Answer 1

Better don't. (Not saying it cannot be tweaked somehow into there, but I think it is not a good idea).

Class diagrams show properties of the actual classes, like access modifiers "private", "public" and "protected", not restrictions on the use cases for the users of your system. A view restriction of clinicians on notes is something which needs to be encoded into the application by certain features, non-features or access rights, and maybe by utilizing database access rights as well. This is a very different level of abstraction than the level a class diagram typically shows. (And don't intermix a class Clinician with the real person which sits in front of a workstation and uses the system.)

A sensible place where you can put such restrictions in UML is a use case diagram, inside the textual description of a use case "View Notes" or "Manage Notes", for example.