I have a question regarding multiple actor in one use case. Here the example of a use case that I have created:
Then, I try to figure out how to create a sequence diagram for that use case. Do I need to split it into 3 sequence diagrams, or change the user into "internal employee". Anybody can help & explain to me the better way to create a sequence diagram for that use case?
Further what in the case when there are more UCs like in this example:
Rather than that I would use a general role (/actor) for the viewer like this:
This makes clear that the role is of interest, not the specific person. When your UC model is done you can also recognize whether you need Manager and the others at all. Only if they have a UC on their own (which I'd guess for some) you keep them. If they are left to appear just as specialization you can also just leave them out of your model.
Re. your additional question: It's no different to what is suggested above:
Still each UC is connected to a single primary actor. That means you would design a single SD per UC with its primary actor only. Of course if you have a complex UC it could result in more than a single SD to picture the whole sequence with all alternatives, but that's another story. It's up to you if you include the HR employee; probably it will make the picture more complete, if included.
