Examines factors that determine user charges based on query processing costs in numeric databases, and analyzes the problem of estimating such charges in advance. An approach to query cost estimation is presented which is based on the relational data model and the query optimization, cardinality estimation, and file design techniques developed in…

Discusses the problems associated with using connect time as the basis of user fees for searching numeric online databases, and proposes a methodology for user charge estimation based on query formulation and results. (87 references) (CLB)

Provides an overview of the development and use of numeric databases, and of the evolution of user charging methods for all online information retrieval systems. The need to provide database users with advance estimates of charges is discussed, and a methodology for charge estimation is presented. (87 references) (CLB)