Sequence Diagram vs Usecase Diagram
I have build a usecase diagram for hotel reservation
Should i build a sequence diagram for each usecase in the usecase diagram, or can i summarize multiple usecase in a single sequence diagram?
Answer
A use case diagram shows how use cases and actors relate to each other and gives a functional system overview.
A use case is graphically represented in an activity diagram where the single steps occur as actions.
A sequence diagram is used to show how objects communicate.
Usually you derive classes and relate them to actions of the use case activities. So when you create a sequence diagram it highlights a certain aspect of the whole system. This highlight is usually spot on and not a floodlight. Putting multiple use case scenarios in a single SD would for sure simply blind any reader instantly.