A use case diagram in software engineering is a visual representation of the relationships and processes involved in a software development project, specifically the use cases that describe how users interact with the system. The diagram provides a high-level overview of the system, showing the actors that interact with the system, the use cases they are involved in, and the relationships among the use cases.
A use case diagram can help software engineers understand the scope and context of the project, provide direction on how the system is used, and ensure that all requirements have been accounted for.
An example use case diagram could look like this:
In this diagram, the actor – denoted by the person icon – is the user interacting with the system. The use cases – denoted by ovals – are the processes and tasks that the user can complete using the system. The arrows indicate the relationship between the various use cases. In this diagram, the user has two use cases: searching for products and ordering products. The dashed arrowed line indicates that searching for products is a prerequisite for ordering products.
Overall, a use case diagram is a helpful tool for software engineers to see the bigger picture of the system, define the scope of the project, and ensure that all user requirements are met.
