How To Create A Class Diagram From A Use Case

Question

Has anyone got any pointers or can help me with doing a class diagram from a Use Case Diagram? Its been a few years since i have done one and i am at a complete loss. Not sure how to link the image straight into the post.

I don't need anything extensive, just very simplistic

Answer 1

A class diagram and use case diagrams are quite different really, they detail different aspects of your design. Think of a use case diagram as something you start off with explaining your system -- a high level interaction between human (various roles in your business/org) to system they touch or use. Then those systems are connected with other systems.

Now a class diagram is quite a bit more detailed it shows the objects or components within a specific use case bubble! Sometimes those classes are database tables, sometimes they are objects. So a class diagram is quite a bit more detailed.

So if you want to go from use case diagram to a class diagram, start with the first system in your use case and detail the components for that item. Classes can represent database tables or actual system objects, it depends on your need and how detailed you want to be to relay your design. Go as deep as necessary to relay your points so who ever is going to build/review your system understands the design.