4. Making the Use Case Diagram

Now that we have gone over what a use case diagram is, how it works, and the key components, we finally have the knowledge required to make a use case diagram of our own. When building a use case diagram, it is important to remember that thoroughness is key. We want to make sure that we convey as much information as we can in order to have a complete diagram (as stated previously, the use case diagram is arguably one of the most important diagrams within UML, as it is the foundation for all other diagrams developed). So before we can actually begin drawing the use case diagram, we need to perform some requirements analysis, to make sure that we have all the information we need. Some key things to analyze would include:

1. Use Cases: Do we have all the functions/events that are necessary for the system to function? Are they organized in a legible and logical manner? Are there common functions between use cases that could be use cases of their own?
2. Actors: Who or what interacts with the system? Are they clearly defined? Are there non-human items that may interact with the system as well? Did you include time as an actor?
3. Associations: How are use cases and actors related? Does it require a description? Are there any use cases that are associated with each other?

These are just a few of the questions that should be asked  before you make a use case diagram. But if you find any issues or additions in the future, don't be afraid to add them at a later time, just be sure to note the additions.

Theses are the steps required to create a use case diagram. For this example, I will use the example of a basic school registration system.

1. Draw a box to represent the information system.
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2.  Identify and add any relevant actors
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3.  Identify and model required use cases
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4.  Add relevant associations between actors and use cases
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To summarize this post and the information in this blog, remember these tips

•Use Case: set of scenarios related to a single goal.

•Use Case Diagram: shows interaction between actors and use cases within a system

•Key elements: System, Actors, Use Case, Association.

•Always document Assumptions!

I hope you have found this information relevant and useful, and I wish you the best of luck in future Modeling projects!