Are these UML Secondory actors mandatory?

I have an issue while creating UML diagram wrt secondary actors.

Issue is in confusion in use of secondary actor.

Use case is for a website and its for account creation.

Usually account is created by Admin ...so use case can be written like

Admin -> Create account <- secondary actor?

bu开发者_如何学JAVAt i need to put secondary actor on the right hand side my question is it mandatory?

if yes .. wht to put there?

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All use case should have a Primary Actor. ( The one who use sytstem to achieve a goal)

and

Use cases may not have Secondary(Supporting) actors. Secondary(Supporting) actors are not mandatory.

and

It is a convention to put primary actors on the left side and secondary on the right side. . You do not have to follow this convention. But this Just make diagram more clear