Association and Relational Icons
Create Association - creates an association. Associations depict the interaction between an actor and a use case. This is the only relationship between actors and use cases.The figure shows all the actors as having an association with use case A. Create Extend Relation - creates an extended relationship. An extended relationship indicates that a “child” use case adds to the existing functionality and characteristics of the “parent” use case. An extended relationship is depicted with a directed arrow having a dotted shaft, similar to the include relationship. The tip of the arrowhead points to the parent use case and the child use case is connected at the base of the arrow.The figure shows an extended relationship between use case B and use case A. Create Include Relation - creates an include relationship. An include relationship indicates that one use case uses the functionality of another use case as a part of its process flow. An include relationship is depicted with a directed arrow having a dotted shaft.The figure shows an include relationship between use case A and use case C. Create Generalization Relation - creates a generalization relationship. A generalization relationship is a parent-child relationship between use cases in which the child use case performs the same task as the parent but in a different way. A generalization is shown as a directed arrow with a triangle arrowhead. The child use case is connected at the base of the arrow. The tip of the arrow is connected to the parent use case.The figure shows a generalization relationship from use case D to use case A.