Maintenance and prototyping at the entity-relationship level: a knowledge-based support

The authors explore the maintenance applications of a knowledge-based tool which has been designed to support the high-level phases of ER (entity-relationship) data modeling in the development of new systems. The ER conceptual schema and the logical relational schema are represented in a knowledge base; the tool provides prototyping features by means of an active representation of those schema which can be exercised with real test data. Changes at the ER level are supported by means of interactive manipulation primitives, rules are added to offer advice on and control of the semantic consequences of changes, and aids to ensure referential integrity constraints in relational databases are included