Create use cases

- Project requirements describe what our stakeholders want a solution to do, but they generally don't provide the context that we need to develop good solutions. We can solve this problem by using our requirements to create use cases. A use case tells the story of how the solutions should work once it's complete. It provides a step by step explanation of a process and what everyone involved needs to do along the way. A single use case could provide the context to support many different requirements. There are a couple of key terms that you need to know. The people and systems that are including in a use case are called the actors, and the steps are called actions or events. Now let's walk through an example and create the use case for ordering pizza at a restaurant. This use case has several actors like the customer, the waiter, and the chef. And since the order needs to be entered into a computer, well the computer's an actor too. Now, what are the steps that occur in the process? The waiter takes the order from the customer, and enters it into the computer. Each of those steps is an event. Then the computer transmits the order to the chef. The chef makes the pizza and the waiter brings the pizza to the customer. There, you've got a simple use case. Sometimes the easiest way to communicate a use case is to write it out, but you can also document them by using diagrams. For example, a swimlane diagram is a special kind of flow chart that shows which actors need to complete each step. Or for more complex use cases, you can use a technique like unified modeling language, or UML to diagram the process. UML is especially helpful if you're writing software and need to understand how the people and the computers are going to interact. You can learn more about UML from several of the courses here in the library. Use cases enhance requirements by providing the context to help everyone understand a process. Using them properly makes it easier for everyone to work together to build better solutions.