Models for object oriented design started to emerge in the 1970s. I the 1980s there was much debate on the best modelling technique. The leading people were Grady Booch (design oriented), James Rumbaugh (data oriented), and Ivar Jacobson (use case oriented). All wored at Rational software and developed a Software Development Life Cycle (SDLC) known as the Rational Unified Process (RUP)
A use case is a set of goal oriented interactions between external actors and a system. A primary actor is one who has a goal that may be acheived using the system. A secondary actor is one who may assist in acheiving this goal.
Define high level sets of activities \
Use cases are represented by an oval with a label inside. \
Actors are represented by stick men. If an actor is not actually a person, it is often better to represent it by a box with the tag <
Generalised relationships are ones where a general use case represents a generalisation of more specific use cases. A generised relationship is represented by an open headed arrow pointing from the specific case to the general case
The relationship of objects within the system and the operations they can perform.