ISMT221 Information Systems Analysis and Design Class diagram Lab 5 Tony Tam

UML diagrams Class Diagram Logical structure of the interacting object-oriented model: object, internal structure and relationship Use Case Diagram Logical level of the interaction between actors and the use cases Sequence Diagram Visual flow of the system logics More a programming view of the system

Class Diagram

Elements of Class Diagram Class Diagram shows the static structure of an object-oriented model, i.e. the object classes Class – Student, University, Car Object – Peter, HKUST, Mercedes S320 Usually done before technical implementation; a good brainstorming tools for system architect.

Some basic notation Class Upper part – Class Name Generic instead of specific… So this should be “Tutor” instead of “TA” Internal structures Middle part – Attributes Bottom part – Operations/ Methods Encapsulate the attributes, and use the access the attributes/ Class Relationship with other Class

… and relationship Relationship To associate classes together 1. Binary association Two classes together, nothing else 2. Association Class Two classes, with a Associative Class for their relationship E.g. is enrollment a class? Only associative 3. Generalization Daughter/ mother’s eyes/ hairs? The subclass possess more attributes of superclass; subclass is also a kind of superclass.