BUSI 3402 Lecture Notes - Lecture 4: Data Flow Diagram, Use Case Diagram
Document Summary
Elements: name, number and description, priority to indicate significance, actor refers to person, system or device that interacts with system, trigger refers to event that causes the use case to begin. Preconditions: conditions that must be satisfied before start of use case. Postconditions: conditions that are completed when use case ends. Source/sink: external entity that is origin or destination of data. Context diagram: overview of system that shows system boundaries, external entities that interact with system, information flows between entities and system. Level 0 diagram: represents system"s major processes, data flows and data stores at the highest level, logic. Matrix representation of the logic of a decision which specifies the possible conditions for the decision and the resulting actions. Condition stubs: lists the conditions relevant to the decision. Action stubs: lists the actions that result for a given set of conditions. Rules: specifies which actions should follow for a given set of conditions, data. Contemporary (ooa) approach: use case diagram.