Cooperative querying in relational databases

This paper proposes an architecture for cooperative access to databases, and describes a cooperative interface for querying relational databases (i.e., an interface that assists non-experienced and casual users to get useful answers from a relational database) which has been implemented based on this architecture. The architecture comprises two knowledge bases which store rules that describe the application domain and that guide the process of query formulation and answering. Queries are formulated using a subset of SQL which does not require the user´s knowledge of the language syntax and of the database structure. The interface uses the rules stored in the knowledge bases to expand the queries and to provide more relevant answers to the user