UML diagrams- use case diagrams

Question

The scenario: Customer goes to the counter and asks the employee to select a specific movie

Which one of the following would be correct?

Answer 1

1] Assumption: Customer and Employee as actors. Movie Selection System ( MSS) as external system

Then the external system is the Movie Selection System and the actor is either the Customer or the Employee. The use case is "Select Movie" or "Select a Movie Seat". There is 1 to 1 relation between the actor to the use case as actor can select 1 movie at a time and the use case will have one MSS and one actor at any given time. But MSS can be asked multiple movies at same time by multiple employees.

Customer / Employee (1) -------- (1) [ Use Case: Select Movie ] (*) ---------> MSS (1)

2] Assumption: 1 Customer and 1 Employee present. If you treat the Employee as the system itself, then the diagram should be directional arrow associated from Customer towards Employee. So maybe it would look like below

Customer (1) -------- (1) [ Use Case: Select Movie ] (1) ---------> Employee (1) .

Since a Customer can select one movie at a time. Each use case at any time can be called by one customer asking any one employee. Also the employee can be asked to select only one movie at any given time. 2nd diagram is close to what I understand as correct

Answer 2

Diagrams 1 and 3 are syntactically incorrect (no need even to read your case study). The arrow you use is a generalization arrow (i.e. more or less inheritance). You can't have this arrow between an actor and a use case, only between two actors or between two use cases.

Diagram 2 seems correct. Use case is associated to the two actors with links. Usually, setting one actor on the left and the other on the right may mean that the one on the left is primary, and the one on the right is secondary.

The primary actor is the one that performs the use case, while the secondary one is involved in the use case but does not perform it. Thus here it seems ok : the employee selects the movie thanks to information provided by the customer.