Use case diagrams are a great tool that can help businesses and developers alike to design processes and systems.
By capturing requirements and expectations from a user’s point of view, they ensure the development of correct and efficient systems that will properly serve a user’s goals.
In this article, we will define what a use case diagram is and provide you with different use case diagram examples.
You can create your own use case diagrams using Venngage’s Diagram Maker and templates. No design experience is required!
Click to jump ahead:
- What is a use case diagram?
- What are the benefits of a use case diagram?
- Types of use case diagrams
- What are the elements of a UML use case diagram?
- 5 Use case diagram examples and templates that you can use
- FAQs about use case diagrams
What is a use case diagram?
A use case diagram is a visual representation of the different ways and possible scenarios of using a system. It illustrates how a user will perform actions and interact with a particular system, such as a website or an app.
For example, this use case diagram depicts the different functions of a banking system for customers:
In Unified Modeling Language (UML), systems are presented at different levels of detail to show a specific perspective in the system’s design. Use case diagrams are considered UML diagrams.
UML diagrams define and organize the high-level functions and scope of a system. By modeling the basic flow of events in a use case, they help identify the goals that you need to achieve with every system-user interaction.
What are the benefits of a use case diagram?
Use case diagrams can aid your development process with the following benefits:
- Guiding development: Use case diagrams can help establish the cost and complexity of your system. It does so by specifying which functions become requirements that will make it to the development stage.
- User-driven approach: Use case diagrams are written in natural language, which helps users easily understand them. Additionally, they provide businesses an excellent way to communicate with customers. Here is a use case diagram example that shows the basic transactional path of a banking customer:
- Simplifying solutions: By breaking down solutions into practical functions or features, use case diagrams can decrease the complexity of the problem that your system is trying to solve.
- Tracking progress: Use case diagrams can be used to monitor which use cases have been implemented, tested, and delivered and help you identify which functions work and which ones don’t.
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Types of use case diagrams
There are many different types of diagrams that can be used for designing and representing systems and processes. As for UML use case diagrams, they are classified into two types: behavioral and structural UML diagrams.
Behavioral UML diagrams
Behavioral UML diagrams provide a standard way to visualize the design and behavior of a system. Under them are 7 other types of diagrams which are:
- Activity diagrams
- State machine diagrams
- Sequence diagrams
- Communication diagrams
- Interaction overview diagrams
- Timing diagrams
- Use case diagrams
As an example, this use case diagram portrays how an ATM system will behave or react when a customer or administrator performs an action.
Structural UML diagrams
Structural UML diagrams on the other hand focus on depicting the concepts involved in a system and how they relate to each other. There are also 7 types of structural UML diagrams:
- Class Diagram
- Component Diagram
- Deployment Diagram
- Object Diagram
- Package Diagram
- Profile Diagram
- Composite Structure Diagram
What are the elements of a UML use case diagram?
Use case diagrams contain a combination of different elements and specialized symbols and connectors. Whether you want your use case diagram to be simple or in-depth, it should include the following basic components:
- Actors – An actor is anyone who performs an action using your system. Actors or users can be a person, an organization, or an external system. Actors are represented by stick figures in a use case diagram. In this example, the functions of a system are modeled for two types of actors: persons and organizations.
- System – The system scope covers a sequence of actions and interactions between users and the system. To depict the system boundary, system boundary boxes are used to signify that a use case is within the scope of the system.
- Use cases – Use cases are the different uses or applications that your system can offer users. Horizontally shaped ovals are used to symbolize use cases while lines are drawn to connect the user to the use case. Here is an example to illustrate the relationship between users and use cases:
- Goals – The goal is the end result of a use case. An effective use case diagram should describe the activities involved in reaching the goals behind each use case.
5 Use case diagram examples and templates that you can use:
Here are some use case diagram templates and examples to guide your diagram creation process:
Retail use case diagram
This use case diagram example depicts the internal functions and employee interactions within a retail system.
It features basic system functions represented by color-coordinated boxes to signify use cases based on the user’s role. A use case diagram like this can be of great use to retail stores with B2C e-commerce systems.
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Restaurant use case diagram
In this example, a restaurant’s daily operations serve as the system, the staff represent the actors, and their tasks are the use cases.
This use case diagram can be particularly helpful to restaurants or fast-food chains in terms of systemizing routine processes and presenting day-to-day activities to employees in a simpler and more orderly way.
Travel use case diagram
Here is a use case diagram that maps out how different types of users can engage with a travel booking website or application.
This comprehensive template includes extended use cases marked by dotted lines and arrows instead of simple lines. It can be scaled down or up for hotels, airlines, and other travel reservation systems.
Banking use case diagram
Designed for automated teller machine (ATM) systems, this use case diagram portrays different types of transactions as use cases.
As this example is very simple and contains only essential elements, it can be adapted for other banking systems like branch banking or online banking.
Consumer electronics store use case diagram
Last but not least, this use case diagram example illustrates how sales and management teams can use a retail system to carry out tasks.
It can be applied to retail systems for consumer electronics and home appliances, fast-moving consumer goods, and other retail sectors.
FAQs about use case diagrams
What is included and not included in a use case diagram?
Use case diagrams describe the relationship between the users, the system, and its use cases. They do not need to go into a lot of detail and explain how the system operates internally. Here is a guide on what to include and what not to include in your use case diagram:
What to include:
- Who is using the system
- How the user will use the system
- What the user’s goal is
- What steps the user takes to accomplish a task
- How the system responds to a particular action
What not to include:
- The order in which steps are performed
- Details about user interfaces
- Programming language
How do you write a use case diagram?
Writing a use case diagram involves deconstructing processes in order to reveal a basic overview of your system. Here are some steps that you can follow:
Step 1: Identify the actors (users) who are going to be engaging with your system. Categorize each type of user based on their roles.
Step 2: Pick one type of user and list what actions they would take using the system. Each action becomes a use case.
Step 3: Create a goal for every use case. Identify what is required from the system to achieve these goals.
Step 4: Structure the use cases. Include in the description for each use case the basic course of events that will happen when a user performs a certain action. It should describe what the user does and how the system responds.
Step 5: Take into consideration alternate courses of events and add them to extend the use case.
Step 6: Repeat steps 2-5 to create a use case diagram for each type of user.
What software is used to create a use case diagram?
There are various tools and software available for creating a use case diagram. For starters, you can try Microsoft Visio which is a diagramming and vector graphics application that is part of the Microsoft Office family.
You can also go for web-based software if you don’t want the hassle of downloading, installing, and updating programs. Venngage’s diagram features include pre-made use case diagram templates that you can customize for your business and development needs.
In conclusion: use case diagrams represent the value that your system can provide users
Creating a use case diagram can help you illustrate how your system can fulfill the needs and goals of your users. Make sure to use Venngage’s diagram maker to create a successful use case diagram for your next project.