Use Case
Use cases serve as process models that employ textual narratives to elucidate the interactions between a system and its users for achieving a specific goal. They are an essential tool in the realm of business analysis, commonly utilized for identifying and elaborating on requirements. Let's delve deeper into the constituents, purposes, and best practices associated with use cases.
Anatomy of a Use Case
Goal and Naming
The overarching objective that the primary actor aims to accomplish is denoted as the 'goal' of the use case. It is customary for this goal to form part of the use case's name, usually articulated as a verb phrase.
Normal Flow
The 'normal flow' refers to the most frequent pattern of interactions between the system and the user. It encapsulates the standard course of actions and reactions that occur under typical conditions.
Alternative and Exception Flows
Aside from the normal flow, a use case also encapsulates 'alternative and exception flows.' These represent the various paths that deviate from the normal flow due to specific conditions or exceptions.
Common Fields
Commonly included fields in a use case might consist of:
- Name: As mentioned, a verb phrase that clearly defines the goal.
- Description: A succinct account of what the use case entails.
- Actors: The roles that will actively partake in executing the use case.
- Organizational Benefit: A rationale illustrating the significance of the use case for either the project or the broader organization.
- Trigger: Specifies the event initiating the use case.
- Preconditions: Outlines the prerequisites that must be met for the use case to commence successfully.
Creation and Timing
Use cases are often formulated subsequent to the development of process flows. This sequencing facilitates the provision of supplementary details for specific steps in those process flows, especially when the interactions between the system and users are intricate. Nonetheless, use cases can also stand alone and be developed in lieu of process flows.
Types of Requirements Addressed
Use cases are primarily employed to identify functional requirements but can also specify nonfunctional requirements or acceptance criteria. However, it's essential to note that nonfunctional aspects, like system speed or durability, are usually not incorporated into the use case itself but are documented separately.
Representation and Documentation
Textual use cases can either be represented through a standardized document template or take a tabular form featuring standardized columns. The chosen format would hinge on the particular needs of the project and stakeholders involved.
Practical Applications
Use cases are especially useful when transitioning from business requirements to stakeholder requirements or even to solution requirements. They serve as a detailed roadmap outlining the steps and conditions necessary for the successful completion of a goal.
Conclusion
Use Cases offer a structured framework to capture, represent, and analyze the dynamic interactions between systems and their users. By detailing the normal, alternative, and exception flows, along with critical attributes like triggers and preconditions, use cases serve as invaluable assets in the meticulous process of requirements gathering and elaboration.