# Use Case Diagram

A use case diagram at its simplest is a representation of a user's interaction with the system that shows the relationship between the user and the different use cases in which the user is involved. A use case diagram can identify the different types of users of a system and the different use cases and will often be accompanied by other types of diagrams as well. The use cases are represented by either circles or ellipses.

# Actor

# Primary Actor

# Secondary Actor

# System

# Use Case

# Relationship

# Association

# Include

# Extend

# Generalization

# Video Tutorials