Practical Application for Software Engineering: UML Case Diagram

Instructor: Scott Tuning

Scott has been a faculty member in higher education for over 10 years. He holds an MBA in Management, an MA in counseling, and an M.Div. in Academic Biblical Studies.

UML case diagrams are perfect for documenting the way in which various user types will interact with an application. It integrates and maps workflow processes to IT systems.

The UML Case Use Diagram

The UML case diagram is used to depict how people in various roles (actors) will use a technology resource (system). Case diagrams mapping actor-system interactions are particularly useful at visually depicting the desired outcome of an interaction (goal). The various user interactions are documented on the diagram using circles that depict a scenario (business case).

UML Case Diagram Application: TreeTrack 2.0

Let's take a look at an example.

At seemingly random intervals, the ash borer beetle makes a run through the country. The events occur as frequently as every two years, but there are also periods of up to 11 years without an infestation.

You've been hired to implement a solution called TreeTrack 2.0. This will be a comprehensive enterprise application that can track nearly all the important aspects of a beetle mitigation project. Let's get started!

Step 1: Identify and Plot the Actors

The ash borer is of interest to a number of different actors including:

  • XYZ Arborists - a company that specializes in prevention and mitigation of diseased Ash trees.
  • The XYZ State University Extension Program - a college with a robust environmental studies program.
  • The community at large, as their parks and homes have ash trees in them.
  • Staff members responsible for various administrative tasks like payroll, accounting, billing, and contracting.

Each of these actors will be represented by a stick figure on the left edge of the diagram. When plotted, they will look like this:

Actors are the people who will interact with the system.
UML Actors

Step 2: Draw System Bounaries

Although you and your company can work almost exclusively out of TreeTracker 2.0, there are a lot of external relationships that can't be managed with TreeTracker alone. In addition to your own company's operations, your systems must work closely with resources from both the university researchers as well your own accounting applications. Once you plot out the system boundaries, your diagram looks like this:

Since not all interaction will occur inside a single system, boundaries are drawn to represent data interactions outside the initial system.
UML Boundaries

Step 3: Map the Use Cases (Scenarios)

Your diagram is coming along nicely, but the core of the diagram isn't tackled until you illustrate the use cases. Use cases are often called ''scenarios'' because they represent one user interaction from start to finish.

In nearly all instances, every actor must have at least one use case, and some have many more. After some thought, you might decide on these use cases for the actors:

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account