In 'Associative Caching' each client computer keeps a copy of its query result sets in its own local database. The purpose is to reduce the size and frequency of queries to the remote data server accessed by wide-area network. For each new query the client tries to find some or all of the required data in its local collection of result sets. This is done by syntactic comparison of the new query with each previous query, to detect overlapping data sets. Attribute-Pair Range Rules are subset descriptors which the server derives from its data, for its own use in query optimisation. These subset descriptors can be further utilized to provide descriptors for each query result set. This new information enables clients to exploit their cached data for syntactically unrelated queries.
Jerome Robinson, Barry G. T. Lowden