C12 Modelling Requirements Flashcards
What is use case diagram?
Use case diagram is UML diagram which shows some business or software system, its external users (called actors), and a set of actions (called use cases) that users of the system should or can perform while using the system. Use case diagrams are used to describe functionality of a system from the point of view of external users.
What is a use case?
Each use case describes a unit of complete and useful functionality that business or system provides to its users, how external user interacts with a system to achieve a desired result. Some examples of use cases: Hire employee, Buy ticket, Place order, Deposit funds.
What is actor in use case diagrams?
Actor represents some group (called “role”) of external customers or users of the business or software system. Actors have some needs and require specific services from the system. Some examples of actors are: Customer, Student, and Passenger. Actor could be not just human but also another system, business, or device.
What is the difference between use case diagram and use case?
Use case diagram shows business or system, its external users, and use cases applicable to the system. Use case represents one specific goal or need of the user from the system.
The <> and <> concepts allow use cases to be connected to each other.
Explain the include / extend concepts.
-The include relationship could be used:
to simplify large use case by splitting it into several use cases,
to extract common parts of the behaviors of two or more use cases.
- The extend relationships are important because they show optional functionality or system behavior. The <> relationship is used to include optional behavior from an extending use case in an extended use case.
What is an entity relationship diagram?
An entity–relationship model describes interrelated things of interest in a specific domain of knowledge. A basic ER model is composed of entity types and specifies relationships that can exist between instances of those entity types.
What is a class diagram and how can it be used?
Image result for class diagrams Class diagrams are one of the most useful types of diagrams in UML as they clearly map out the structure of a particular system by modeling its classes, attributes, operations, and relationships between objects.
