System & Requirements Documentation PDF

System & Requirements Documentation CHEAT SHEET We’ll be focusing on… Use Case Diagrams Entity Relationship Diagrams Dataflow Diagrams Use Case Diagram Why Use Cases? Clearly denotes the scope of the system by defining: Who will be using it What will they be using it for Use Case S...

System & Requirements Documentation CHEAT SHEET We’ll be focusing on… Use Case Diagrams Entity Relationship Diagrams Dataflow Diagrams Use Case Diagram Why Use Cases? Clearly denotes the scope of the system by defining: Who will be using it What will they be using it for Use Case Symbols Actor – which is a user of the system Activity – which is what a user may use the system to do Activity/Use Case Special Relationships Some activities may have special relationships with others. There are two types of relationships: includes and extends. An includes relationship refers to an activity that MUST occur if the related activity is performed by the actor. An extends relationship refers to an activity that MAY occur if the related activity is performed by the actor. Direction of Special Relationships Includes Main Second Main Second Extend s Entity Relationship Diagram Entity Relationship Diagram The purpose of an ERD is to identify and communicate the key components of a system and their corresponding attributes and the relationships these components have with each other. Shapes of an ERD Entity Generalizati on (IS A) relationshi p Attribut e Types of Relationships (Cardinality) One to One (1:1) One to Many (1:M) Many to Many (M:M) Special Relationships Aggregation – refers to an entity having a relationship with an existing relationship. Data Flow Diagram Data Flow Diagram The purpose of a dataflow diagram is to capture the movement and transformation of data as it moves through the various processes of a system. Shapes of the DFD System User Proces s Data flow