Use Case case study – UML Modelling

In this Use Case case study, I am going to present a case study of the airport check-in system. The case study includes the identification of actors, use cases and scenarios including activity diagrams. I have used a generic case study approach and can be used in any software project. This case study is useful for every business analysis study.

The sequence diagram for the same case study will be covered in some other post as that would have made this post too long.

Case study description

This proposed software system is to be designed to allow passengers to check in and get the boarding pass for flying. The baggage can also be checked in, which is optional. The check-in can happen by the counter clerk or by the passenger using the kiosk.

The system should allow individuals as well as groups of passengers to check in through the system. The boarding pass can be issued through this system. Passengers below 4 yrs need not have tickets. The airport also allows provisioning for the special needs of passengers like wheelchairs etc.

The system should also be able to capture the fact that the baggage for a passenger is screened by security.

Use Case Modelling steps

Use case modelling can be done in multiple ways. One of the standard processes is known as Rational Unified Process (RUP), this process is put forward by Rational Inc., now under Oracle.

In this article, I am going to suggest a process, which I used in my projects in various software companies. As per this process, the steps involved are as follows, these steps are for complete system analysis and design using UML models. However, in this article, we will look at only use case modelling steps:

  • Understand the business domain, context and needs
  • Conduct Stakeholder Analysis
  • Interact with stakeholders to understand stakeholders needs
  • The following steps are conducted iteratively:
    • Find structural elements/functions – functional decomposition
    • Use cases identification & create use case model
    • Identify scenarios
    • Create activity diagrams
    • Create sequence diagram, if needed
    • Identify classes and build logical data model
  • System design
  • Coding
  • Testing
  • UAT
  • Go Live

Step1: Identify actors

The first step is to identify the actors from the given requirements. Actors are external entities, who interact with the system, to be developed. All the nouns used in the requirements could be actors. In our case, the possible candidates for being actors could be:

  • Passenger
  • Passengers with age <= 4 yrs
  • Passengers with special needs
  • Group of passengers
  • Check-in clerk

Identification of actors is an iterative activity, where we can refine the selection of actors. If you look at the actors' list, you can see that there are multiple types of passengers. This means that an actor namely Passengers has related actors. The actors can be shown as shown below:


Step 2: Identify use cases

Once we have identified actors, we can focus on the interactions of the actors with the system. In our case of the airline system, we can identify the following use cases:


This functional mapping is an excellent way of functional decomposition as well as identification of use cases. Based on the above functional map, we can go ahead to create the use case model. A detailed use case model is shown below:


The use cases are kept within the system boundaries with proper “Include” and “Exclude” relationships.

If you want to brush up on your basics of Use cases and UML, you can read this blog: What Is Use Case Basics & Diagrams?

Step 3: Identify scenarios

Once we identify the use cases and build the use case model, the next step is to identify scenarios. The scenarios add details to the use case model. Scenarios also help in identifying business processes and creating activity diagrams.

Typically speaking, every use case may result in one or more scenarios. However, it’s not mandatory to make activity diagrams for each of the use cases. Every model diagram is created only if it helps in understanding the system better.

Scenarios can be of two types:

  • Success scenario, when everything works fine
  • Error/Alternate scenarios

Let’s see the scenarios for the check-in process:-

Success Scenario: Check-in process getting completed without any issues

  • Individual puts the baggage for check-in and stickers
  • Shows the ticket to the booking clerk at the booking counte
  • The booking clerk enters the PNR number and verifies the data
  • The booking clerk asks for an ID card and verifies
  • The passenger puts the baggage and the weight is checked by the booking clerk
  • The baggage stickers are printed and attached to the baggage
  • The boarding pass is issued to the passenger

Alternate Scenario: Check-in process for Individuals having special needs

  • The booking clerk enters the PNR number and verifies the data
  • Identify the passengers with “Special needs”
  • An alert is sent to the customer service desk

There are other alternate scenarios in this case, I am not writing the steps for them. You can try that as exercise.

i. Alternate Scenario: Baggage weight > Allowed limit
ii. Alternate Scenario: Valid ID card not available
iii. Alternate Scenario: Passenger checks in using Kiosk Having identified the scenarios, the next step is to create the activity diagram.

Step 4: Creating activity diagrams

The activity diagrams can be created on the basis of identified steps and scenarios. You can use a tool to create the activity diagrams or use Microsoft Word or Powerpoint as well.

For our case study, the activity diagram is:

Activity-Diagram- Airline-System

This is a type of case study, which are part of all of our business analysis courses, where we help participants to do it themselves so that they can get hands-on experience.


The use of use cases is an essential technique for business analysts to understand the requirements of stakeholders and build effective software solutions. Through the case study discussed in this article, we have seen how use cases can be applied in real-life scenarios to identify and analyze business requirements, document functional specifications, and develop robust software solutions that meet customer needs.

By following a structured approach to use case development, business analysts can ensure that the software solutions they develop are aligned with business objectives, meet user expectations, and deliver measurable business benefits.

Have you considered getting certified in business analysis but are unsure of which certification to pursue?

Consider getting certified as a Certified Business Analysis Professional (CBAP) by Techcanvass. The CBAP certification is a globally recognized certification that validates your expertise in business analysis and positions you as a leader in the field.

With Techcanvass's CBAP certification training program, you will gain a competitive edge in the job market and open up opportunities for career growth and development. In our training program, we cover tools like UMLet, yUML, and WebSequenceDiagrams. You will get access to all the study material, live instructor-led training, doubt-clearing sessions, and much more.



Leave a comment

Your email address will not be published. Required fields are marked

Comment inserted Successsfully

Please login to Comment


Alternate Text


Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text

Related Blogs


What Is ECBA Certification?


Product Owner vs Business Analyst vs Scrum Master


ECBA Exam Passing Score


ECBA Exam Questions


Business Analysis Body of Knowledge Guide (BABOK Guide)


Which Business Analyst Certification is Best?


How to Become a Business Analyst In India?


How To Become a Business Analyst Without IT Background?


Top 10 Challenges Faced by Business Analysts


How to Handle Difficult Stakeholders?


What Are The Roles & Responsibilities of A Business Analyst?



What Is CBAP Certification?


What Is CCBA Certification?


CBAP Exam Passing Score


CCBA vs CBAP- Which Is Better To Study For?


What is The Value of CBAP Certification?


    Grab offer

    Copyright © Techcanvass | All Rights Reserved