What is Use Case Diagram UML | Tutorial w/ Examples

What is the meaning of a USE CASE DIAGRAM?

A use case diagram is a type of Unified Modeling Language (UML). It is a graphical representation of how would the user interact with your system. Use case diagram also depicts the system’s numerous use cases and different sorts of users, and is frequently supplemented by other diagrams to supports its ideas. Example of diagrams that could support the ideas in UML use case diagram are DFD, ERD and many more.

The use case diagram is one of the UML diagrams that helps in emphasizing the important processes and flow of your project. Through this diagram, your readers and user will be able to understand the details of each processes and their function or work. The use case diagram can summarize the details of your system’s targeted users or also known as actors. Their interactions with the system in the Unified Modeling Language (UML).

Know the BASIC COMPONENT of the USE CASES:

Before we build our use case diagram both the GENERAL and the SPECIFIC, we must know and understand first its components. The components used in building our UML USE CASE DIAGRAMS ARE:
• the Use Cases – the use case are the ellipses or circle symbols. This symbol will illustrate the processes included in the system. It could also show the sub process from the main processes.
• the Actors – the actors are the users of the system. it could be single, dual or multiple depending on the scope of the system. the symbol of the actor are in a form of an icon showing a stick man. It will help the readers as well as the users know their roles to the system.
• the System – the system comes with a rectangular container symbol. It holds all the processes included in the system and acts as the scope illustration.
• the Lines or Arrows – are the indication or connection to which will the process be connected.

How to create a USE CASE DIAGRAM?

Now, to create a use case diagram, you will have to be familiar with its symbols and their function to achieve a well-detailed UML use case diagram. Then your use case diagram must present the flow of your system such as its’ scenarios and application and most of all, it must illustrate on how would it interact with the user.

You also have to make sure that the requirements of the project is well-explained and are met in the use case diagram.
Use case diagrams UML are useful for:
• Representing the objectives of user-system interactions
• Defining and structuring a system’s functional needs
• Defining a system’s context and needs
• The basic flow of events in a use case is modeled.

Here is our full video for the Use Case Diagram Discussion that will surely help you with your Capstone Project building.

Now, let us start creating an example of a use case diagram UML. The first part in creating the use case is known as General Use Case Diagram and here are the illustrations:

Examples of Use Case Diagram as UML Sample

Here are the example of USE CASE DIAGRAMS that serves as samples for UML DIAGRAMS.

  1. Example of Use Case Diagram with Single User


    Example of Use Case Diagram with One User
    This illustration shows a General Use Case Diagram with a single user. As you see, there are general processes that are connected to the user which will serve as what the required form project. The number of the main processes may vary depending on the scope of a specific project.

  2. Example of Use Case Diagram with Dual Users

    Example of Use Case Diagram UML for Multiple User
    Now I present to you one of the example of Use Case Diagram UML which is with dual user. As you see there are processes that are connected to one actor or user, but then the other process is also the other one. And that means that the processes can only be manipulated or used by the connected to a certain user. So the other user will not be able to use it.

    Example of the system that uses this USE CASE DIAGRAM are System that has client side and admin side system just like e-commerce websites and reservations systems.

  3. Another Example of Use Case Diagram with Dual Users

    Another example of Use Case Diagram UML

    Here is another example of UML USE CASE DIAGRAM with dual users that are both connected in the some processes. This illustration means that the other processes can be manipulated or used by both of the users. The good example of this Use Case Diagram or scenario would be Log-in System, ATM System and other systems that requires security in both admin side and client side.

  4. Example of Use Case Diagram with Dual Users

    Example of General Use Case Diagram with Multiple Users

    Here is the last example for your General Use Case Diagram which has 4 users. Actually, your ACTORS could be many as possible as soon as it corresponds to the targeted users of your project. It must also meet the needs or requirements of the system.

    What I’m trying to say about this sample general use case diagram is, you have to provide all the general processes regardless how many it is as long as it correctly explains the whole scope of your project. It is as well as for the actors which will use the system or the project.

Now after knowing how to create the General Use cases, Let’s proceed to the specific use cases. These are the part of Use Case Diagram UML that explains the sub processes included in the main processes stated in general use case. Then these sub processes has its arrows that were labeled with “<<include>>” and “<<extend>>” which will declare if they were required or optional only.

Example of Specific Use Case Diagrams:

Example of a Use Case Diagram using Include and Extend
Example of a Use Case Diagram using Include and Extend

The figures shows an example of a Specific Use Case Diagram scenario. It is the done by breaking down the main process into its sub processes to determine the components or included activities to achieve the output from that main process. That will then give the users and readers about the core functions and expected activities once the system is done.

This use case diagram design would be much easier to create if you have the list of activities and full idea on how the system would work. And to create this UML use case diagram, you need to ask information from the targeted users to be able to meet their needs once you applied it to your system.

Take Note! This UML Use Case Diagram is a design that you will apply to your software development so you better do it right and proper. That means that you should be responsible while creating this design so you could achieve and meet the needs of your client or targeted users.

This time, I will give you an example of use case diagram using include and extend. It will be your guide you you create your own use case diagram for you project.

EXAMPLE of USE CASE DIAGRAM UML using EXTEND and INCLUDE

Use Case Diagram UML Example

Our example for main process is the MANAGING and SECURING of RECORDS and its possible sub process were the validation of data, saving of data and modifying of data.

So as it was said earlier, the extend and include were indication about the role of each sub processes. As you see through the diagram, the indication of the sub processes validation and saving of data were include. It is because these processes are pre-requisite of the main process to achieve and meet the goal of Managing and Securing of Records. Meanwhile, the modifying of data was labeled extend but it doesn’t mean that it is not needed. It is just because, the modifying of data is still part of managing data but it is just optional. It will only be done when requested but not at all times.

Conclusion:

The reason why you should create the UML Use Case Diagram is not only to have a designed blueprint for the software, but also to understand fully the work and core functions of the proposed system. So you need to learn the meaning and understand the symbols through the given example of use case diagrams.

And that is all for today’s discussion, and I hope that this helped you in knowing and understanding the UML Use Case Diagram.

Inquiries:

Now let e ask you something. what have you learned through the discussion? Do you have the ideas for your project? I yo don’t we have the list of examples below which you can download and use for your own, ! Just check it out.

If you have thoughts or questions about our UML Use Case Diagram discussion, do not hesitate to comment it down. That will mean so much for me. Thank you so much and have a good day.

Recommended Examples of UML Use Case Diagrams:

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