Explain the purpose (using only two sentence in each case) of eachof the following

components of UML

• Use case diagram

• Use case description

• Class diagram

• Sequence diagram

• Business or Domain model

UML - Unified Model Language

Explanation:

Use case diagram:

A use case diagram is used to tell how many ways a user can interact with a system. We use special symbols and connectors to build use case diagrams.

We use horizontal shaped ovals to represent use cases, stick figures to represent actors, lines to represent associations between use cases and

actors, packages to put elements into groups.

Use case description:

By the name itself, we can say that it is used to describe the activities of user that he can do with the system and how the system responds to those. Before use case diagram created, we need to write a use case description.

Class diagram:

UML diagrams are of two types. They are,

Structural UML diagrams Behavioral UML diagrams

A class diagram comes under Structural UML diagrams.

Classes are building blocks of an application that uses OOPs concepts. Class diagrams are used to represent classes, relationships, association,

interface.

Sequence diagram:

A sequence diagram comes under Behavioral UML diagrams. It is used to tell the sequential order of objects' interaction. We have many notations in this diagram like actors, lifeline, create message, delete message, lost message, found message etc. It is used to tell how messages move between objects in a system.

Domain model:

A domain model is a visual representation of real - situation objects. In UML, the Domain Model is illustrated with a set of class diagrams