A methodology for creating user views in database design

Reviewer: Pericles Loucopoulos

View integration is arguably one of the most important and at the same time problematic activities in logical database design. Its major objective is to reconcile individual user views, merging them into a global conceptual schema. The need to resolve syntactic and semantic diversities arising in user schemata has led to the development of a number of methodologies that promote a systematic approach to the process of view integration. More recently, knowledge-based technology has been employed to assist database designers in integrating user schemata. This paper describes an expert system known as the view creation system and a set of design steps which, according to the authors, should lead to a well-formed logical schema. The approach adopted is based on the well-known entity-relationship model. The system identifies and resolves inconsistencies, redundancies, and ambiguities, and eventually produces a normalized relational representation. The paper gives a detailed account of the rules in the system's rule base, which consists of procedural as well as production rules, and describes the step-by-step process adopted by the system. The value of this paper is in its detailed description of the view creation and integration expert system. It should be a useful reference for researchers engaged in developing expert systems to assist in the specification and design of data-intensive systems.