You now have a high-level Use Case Diagram and a solid list of candidate use cases—excellent progress. But high-level models are intentionally broad and rough: some use cases overlap, others depend on shared behavior, and a few represent optional or conditional paths rather than core functionality. The purpose of Use Case Refinement and Relationships is to take that initial sketch and evolve it into a precise, professional, and maintainable model that truly reflects how the system works in the real world.
This module focuses on two powerful, interconnected activities:
- Intelligent identification of relationships — recognizing when one use case reuses behavior from another («include»), extends another under certain conditions («extend»), or generalizes/specializes another (generalization — less common but useful in some domains).
- Automated and guided refinement — using Visual Paradigm’s AI Use Case Diagram Refinement Tool to analyze your current diagram, suggest appropriate relationships, and transform the basic overview into a clean, architecturally sound diagram that follows UML best practices.
The result is a refined Use Case Diagram that is easier to understand, reduces redundancy, improves traceability, and sets up downstream modeling (detailed flows, activity/sequence diagrams, test cases) for success.
Why relationships matter so much:
- They eliminate duplication → Shared steps (e.g., “Authenticate User”) are modeled once and reused.
- They express variability → Optional or conditional behavior (e.g., “Apply Discount Coupon” only when a promo code is entered) is clearly separated.
- They improve communication → Stakeholders immediately see mandatory vs. optional paths and shared responsibilities.
- They prepare for detailed specification → Relationships guide how flows are written (main flow vs. included sub-flows vs. extension points).
Visual Paradigm’s AI accelerates this traditionally tedious process by:
- Analyzing the names, actors, and context of your use cases
- Proposing «include» and «extend» relationships based on semantic similarity and common patterns
- Suggesting refinements such as renaming for consistency, splitting oversized use cases, or merging near-duplicates
- Regenerating an updated diagram with clean arrows, proper directionality, and readable layout
You always review and approve every suggestion—AI proposes, you decide.
Practical Examples
Example 1: GourmetReserve – Mobile Dining Reservation App
Initial (unrefined) diagram issues:
- “Book a Table” and “Pre-order Meal” both show separate connections to “Process Payment”
- “Receive Booking Reminder” appears standalone
- “Manage Reservations” includes steps that overlap with “Cancel Reservation”
AI-suggested refinements & relationships:
- «include» → Authenticate User (added as a new foundational use case that Book a Table, Pre-order Meal, Cancel Reservation, and Manage Reservations all include)
- «include» → Process Payment (Book a Table and Pre-order Meal both mandatorily include Process Payment for deposit/confirmation)
- «extend» → Apply Discount Coupon (extends Book a Table at the “enter promo code” extension point—only happens if user provides a code)
- «extend» → Handle Waitlist (extends Book a Table when no tables are available—conditional behavior)
Refined diagram outcome:
- Cleaner diagram: fewer direct lines from Diner to low-level use cases
- “Authenticate User” becomes a central hub with multiple «include» arrows pointing to it
- Extension points are clearly marked on Book a Table oval
- Stakeholders immediately see: “Booking always requires payment and authentication, but discounts and waitlisting are optional extras.”
Example 2: SecureATM – Next-Generation ATM Network
AI-proposed relationships:
- «include» → Authenticate User (Withdraw Cash, Check Balance, Transfer Funds, Deposit Check all include this mandatory step)
- «include» → Validate Transaction Limits (Withdraw Cash and Transfer Funds include this to enforce daily/withdrawal limits)
- «extend» → Request Additional Authentication (Biometrics) (extends Withdraw Cash for high-value transactions > $1,000—conditional security)
- «extend» → Print Receipt (extends most customer use cases at the end—optional but common)
Visual result:
- Central “Authenticate User” oval with many incoming «include» arrows
- Clear separation: core banking actions always require authentication and limit checks; extra security or receipts are conditional extensions
Example 3: CorpLearn – Corporate E-Learning Platform
Common AI-suggested refinements:
- «include» → Authenticate via SSO (Enroll in Course, Complete Learning Module, Take Assessment all include this)
- «include» → Record Learning Progress (Complete Learning Module and Take Assessment both include this for tracking)
- «extend» → Request Manager Approval (extends Enroll in Course for optional/high-cost courses)
- «extend» → Issue Certificate (extends Take Assessment only on passing score—conditional outcome)
Refined diagram benefit:
- Reduces clutter by factoring out repeated authentication and progress-tracking steps
- Clearly shows that certification is not guaranteed—it’s an optional outcome of assessment
Key Takeaways for This Module
By the end of Module 3, you will have:
- A refined Use Case Diagram with meaningful «include» and «extend» relationships
- Fewer redundant lines and clearer separation of mandatory vs. optional behavior
- A model that is much easier to extend into detailed flow-of-events specifications (Module 4)
- Confidence that shared and variable behavior has been explicitly modeled rather than duplicated or hidden
This refinement step is what separates a quick-and-dirty sketch from a maintainable, scalable requirements model. The AI removes the mechanical work of drawing arrows and spotting patterns, while your domain knowledge ensures the relationships make real business sense. With a polished, relationship-rich Use Case Diagram in hand, you’re ready to dive into detailed textual specifications—where the real precision begins.