1. WHAT IS A Use Case Diagram?
An illustration of a system’s intended functions (user goals), its surroundings (actors), and relationships between the user goals and actors
Unified Modeling Language

2. EXAMPLE

3. EXAMPLE

4. Step 1: Identify System Domain
Select an entity as a focal point
Draw a box
Label the system domain

5. Step 2: Identify Actors
Identify the entities that have direct interaction with the system domain
Draw a stick figure for each actor

6. What is a Primary or Secondary Actor?
Primary actors initiate interaction with the System Domain to achieve a goal
Who “Knocks”?
Secondary actors are called by the System Domain for assistance to achieve the primary actor’s goal
Tip: Position Primary Actors on the left side and Secondary Actors on the right side of the System Domain

7. Step 3: Name user goals
Identify WHY an actor would initiate interaction with the System Domain
Draw a horizontal ellipse or oval
Goal is stated in verb-noun format
Example Goals:
Search for Account
Apply Payment
Open New Account
Search for Account

8. Step 4: Connect Actors to Goals
Primary actors initiate interaction with the System Domain to achieve a goal
Secondary actors are called by the System Domain for assistance to achieve the primary actor’s goal
Primary Actor
Secondary Actor