Archive of Requirements Models Articles

In this article, we build on our ability to represent straight forward business relationships in UML class diagrams. These relationships describe how two objects are related to each other. Representing relationships in class diagrams helps us to better understand the domain and helps us to uncover hidden requirements. Occasionally, we have to deal with more complex relationships that involve more than two objects to properly describe. This does not happen as frequently, but when it does, our modeling efforts are more likely to uncover overlooked requirements. In this article we learn how to describe relationships that involve more than two objects.

The hardest part of gathering requirements effectively is uncovering the requirements that people don’t immediately tell you. You have to ask the right questions. And one of the best ways to find the right questions to build a class diagram of the business domain. This article continues our introduction to class diagrams.

UML Class Diagrams are very effective at uncovering requirements. They give us insight into how the business thinks about objects and their relationships. And from that understanding, we think to ask questions we might otherwise overlook. In this part of our series, we look at how to represent when one object is made up of other objects. The two types of relationships we explore are composition and aggregation.

We continue our exploration of UML Class Diagrams with this article that explores how to represent basic business relationships in a class diagram. Drawing these relationships can dramatically clarify requirements documents. Using a class diagram to supplement other requirements documents provides for a centralized reference that enables a shared understanding of the problem domain. That understanding prevents mistakes in interpreting requirements.

UML Class Diagrams can be used not only for documenting software design, but for documenting software requirements. One of the challenges in writing clear, unambiguous requirements is being precise about what a particular word means. This is especially true with symbolic terms like “quote” or “customer” - where everyone knows what they mean - but they mean different things to different people.

We’ve been promoting use cases as the right way to approach agile requirements, and in a recent article, Alistair Cockburn stresses the importance of use cases. Over the last three years, he has found that teams that avoid use cases consistently run into the same three problems. We defer, of course, to Alistair as the expert. But we’ve been independently promoting this practice too. So today, we get a cookie!

Too much information about requirements or too little? Too much documentation or too little? Use the NICE framework to get it just right.

How do you approach starting a small requirements project as part of a large initiative within a massive enterprise? Do you boil the ocean? Your customer knows she needs “requirements” to give to her development team. She asks you - what will you deliver, and how long will it take? Great questions. If you have to write a statement of work, with time/cost estimates, and a list of deliverables - what would you do?

Learning how to write use cases can be tough, but it is simple compared to the balancing act of determining which use cases to write and how to manage the expectations of all the stakeholders that are involved. It can be a difficult balancing act to prioritize use cases to assure that you meet the goals of the business while satisfying the needs of the users.

We use actor hierarchies to organize the different users of a system. Different people play different roles, and thus do different jobs. We use different actors to identify and organize those people. When deploying a system globally, we usually discover people that do the same jobs, but do them differently. Incorporating the notion of personas lets us deal with this.