Summary of several relationships that need to be used when reading / designing UML diagrams:
1 Dependence: The weakest relationship, a dependence B, that is, a statement of A or the header of the INCLUDE C class.
2 Relation: is called 'acquaintance in design mode. Two classes with this relationship do not have a relationship, and there is no responsibility to create and destroy each other, just there is some kind of call relationship.
3 Gathering: and associated comparison imagination, the exact meaning of aggregation B refers to: A member of the Class C class is a pointer to the Class B instance, and the Class B object instance is not implied in the configuration of the A object, and must be constructed by other ways, However, the structural Class B object instance must be destructed when the Class A object is destructure.
4 Contains: In fact, the value aggregation, A contains the exact sense of B, and a member of the class A is a class Class B object instance, and the Class C is constructed at the time of Class A, and the Class C is also destructed. .
5 Inherit: It is easier to understand.
