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Use-case descriptions

A Use Case describes the interaction between a user (often called an "actor") and the system to achieve a specific goal. It provides a step-by-step account of how the system behaves from the user's perspective.

Use cases are valuable for understanding how users will work with the system and for defining the functional requirements in a more narrative and sequential format.

Key Components of a Use Case​

Use cases typically include the following components:

  • Use Case Name: A short, descriptive name for the goal (e.g., "User Logs In").
  • Actor: The user or external system initiating the use case.
  • Triggering Event: The action that starts the use case.
  • Normal Flow (or Basic Path): The step-by-step "happy path" where everything goes as expected and the actor achieves their goal.
  • Alternate Flows: Other scenarios or exceptions that can occur, such as user errors or system errors (e.g., "Invalid Password Entered").
  • Preconditions: Conditions that must be true before the use case can start.
  • Postconditions: The state of the system after the use case is successfully completed.

Often User stories are used to help generate Use Cases. They are short, simple descriptions of a feature told from the perspective of the person who desires the new capability, usually a user or customer of the system.

As a [type of user], I want [some goal] so that [some reason].