ABSTRACT
This chapter reviews the best, or at least the most commonly used, practices for modeling and documenting requirements. A well–defined classification system, or taxonomy, can help with the issues. This technique is especially effective when working with the customer in a requirements session. A good taxonomy can help with deciding what the customer should or should not be involves with from a requirements gathering standpoint. Sequence–based classification recognizes that different levels of the organization have different requirements of the product being developed. When sophisticated business computer systems became more prevalent, the need for an organized approach to develop those systems became a higher priority. Some people referred to it as structured design; another popular phrase was information engineering. The basic concepts of this approach were to model data and processes separately, often in a functional decomposition diagram and an entity relationship diagram, and then model the interaction between data and process in a data flow diagram.
