All About Use Case Diagram

All About Use Case Diagram

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Esha Gupta
Associate Senior Executive
Updated on Oct 3, 2023 11:29 IST

A Use Case Diagram provides a high-level view of the system’s functional requirements and how different actors interact with it.


Use Case Diagram is a visual representation that illustrates the interactions between external actors and the system under consideration in achieving specific goals. It’s part of the Unified Modeling Language (UML), a standardized language for specifying, visualizing, constructing, and documenting the elements of software systems.

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Significance of Use Case Diagram

  • It helps gather and present a system’s functional requirements. It ensures that all stakeholders have a shared understanding of the system’s capabilities.
  • They serve as a tool for communication between various stakeholders, allowing for a common ground to discuss system functionalities.
  • They help maintain a user-centred focus, as they are built around user actions on the system, encouraging a design that meets user needs.
  • Serve as a part of the system’s documentation, helping to illustrate the system’s functionality concisely and visually.

Components of Use Case Diagram

  1. Actors: These are the entities that interact with the system. They can be individuals, groups, or external systems.
  2. Use Cases: These are the specific actions or processes that the actors can perform within the system.
  3. System: This is the overall system being described. It is sometimes represented as a rectangle that encompasses all the use cases, indicating the boundary of the system.
  4. Relationships: These are the connections between actors and use cases, indicating how they interact.

Symbol Table


Now, Let’s Take an Example & Make a Use Case Diagram

Let’s take an e-commerce platform example. We aim to visually represent this system using a use case diagram, highlighting the actors, use cases, and their interactions.


  1. Customer: Our first key player is the “Customer,” depicted as a stick figure. Customers are the heart of our platform, engaging in various activities.
  2. Product: The “Product” actor represents the items available for purchase, each with unique attributes.
  3. Order: The “Order” actor symbolizes the transactions initiated by customers to buy products seamlessly managed by our platform.

Use Cases:

  1. Place Order: This use case allows customers to initiate the process of placing an order. It serves as a pivotal step in the shopping journey.
  2. Add Product to Order: Another critical use case, “Add Product to Order,” enables customers to curate their orders by adding products with desired quantities.


  1. Places: The “Places” relationship showcases how “Customer” interacts with the “Place Order” use case. Customers can initiate multiple orders, establishing a one-to-many relationship.
  2. Contains: “Contains” is a key relationship between the “Order” and “Product” entities. It signifies that an order can contain multiple products, creating a many-to-many association.

Use Case Diagram



Thus, a use case diagram is a valuable visual representation tool used in system analysis and design to illustrate how actors interact with a system or software application. It provides a high-level overview of the system’s functionality, focusing on the interactions between actors and the use cases that the system provides.

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About the Author
Esha Gupta
Associate Senior Executive

I'm Esha Gupta, a B.Tech graduate in Computer Science & Engineering, specializing in Front End Web Dev. I've interned at GeeksforGeeks & Coding Minutes, fueling my passion for crafting appealing and functional digit... Read Full Bio


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