An object-oriented query processor that produces monotonically improving approximate answers

An object-oriented query processor is described that makes approximate answers available if there is not enough time to product an exact answer or if part of the database is unavailable. The accuracy of the approximate result produced improves monotonically with the amount of data retrieved to produce the result. The query-processing algorithm is based on an approximate relational data model and works within a standard relational algebra framework. The query processor maintains an object-oriented view on an underlying level and can be implemented on a relational database system with little change to the relational architecture. It is shown how a monotone query-processing strategy can be implemented, making effective use of semantic information presented by the object-oriented view