Declarative approach to information systems requirements

摘要

The specification of requirements is among the most critical activities of information system development, and yet it is very prone to errors. A number of actions are proposed here to improve the situation: (1) shifting the concern from the target system towards its environment; (2) using an expressive language close to the natural way future users of the system express their requirements; and (3) using a formal language to ensure unambiguity, and to provide the deductive capabilities that will help in validating the requirements. A requirements expression language called ERAE is presented, which is inspired by some of the knowledge representation techniques in artificial intelligence, and by the so-called ‘declarative’ conceptual modelling languages in databases. The author also illustrates how the accompanying methodology makes the best use of the language's characteristics.