Include Use Case Diagram (UML)

Question

I have seen many use case diagrams where a use case can be included to only 1 other use case, is this right or wrong? I have the understanding that in order for a use case to be included, it must be included to minimum 2 other use cases to be considered. If this is true(minimum 2 use case to be considered an include), if its just linked to 1 other use case, do i just use a normal association? thank you

Answer 1

This is a recurring question and often interpreted the wrong way. Include does not mean "call" in a functional analysis sense. It means "this is a use case which can optionally be included". E.g. if you have a tool box you sell with different tool sets (different licensing for software). When you model use cases you synthesize single actions in a form so they build a set that returns some value to the actor. You will not divide pieces of value into smaller ones.

Use cases are about synthesis, not about analysis. When your use case diagrams start resembling spider webs then your design is broken.