Monotonically improving approximate answers to relational algebra queries

Abstract

A query processing method that produces approximate answers to queries posed in standard relational algebra is presented. This method is monotone in the sense that the accuracy of the approximate result improves with the amount of time spent producing the result. This strategy makes it possible to trade the time to produce the result for the accuracy of the result. An approximate relational model that characterizes approximate relations and a partial order for comparing them is developed. Relational operators which operate on and return approximate relations are defined.<>