Activity: Develop Business-Modeling Guidelines

Before you start to describe use cases, you must make several decisions about use-case modeling; for example, whether or not to prototype the user interface and which style guide you will use to describe use cases.

Document in the Business-Modeling Guidelines all decisions that you make regarding any guidelines and strategies for business modeling.

1. Decide the Level of Detail for the Business Modeling
   
   If your understanding of the organization in which the system is to be used is clear or is already described in a satisfactory fashion, you can choose to perform no business modeling at all in your project.
   You can also choose to perform what often is referred to as domain modeling, which means that you will perform no business use-case modeling, but you will develop business entities in the business object model.
   The third alternative is to do "complete" business modeling, which means that you will develop both a business use-case model and a business object model.
   
2. Decide How to Write Business Use Cases
   
   To avoid style inconsistencies, decide on a style for describing use cases early in the project. Decide on one common way of describing business use cases. Keep in mind the advantages and disadvantages of a common style.
   
   Remember the most important thing about use cases is that they are written in such a way that your customer/user representatives/reviewers understand what kind of system you are offering them.
   
   For more information about how you should write a business use case, see Activity: Detail a Business Use Case.
   
3. Decide When to Start Using Relationships
   
   Decide when and if you should start using the three relationships in the business use-case model: actor-generalization, uses-relationship, and extends-relationship. As a rule, you should not use these relationships in the first versions of your business use-case model, as they make the model more complex, and difficult to understand.