Collaborative query processing in DKS controlled by reducts

Abstract

Traditional query processing provides exact answers to queries. In this paper, we introduce, so called, non-local queries which allow us to use attributes outside the local domain. Definitions of these attributes, if only exist, can be extractedfrom databases at other sites. Before, these definitions can be locally applied, problems related to their different semantics have to be resolved first. Rough-ontology is one of the possible tools which can be usedhere quite successfully to tackle the problem.We introduce a tree-resolution for a non-local query which helps us to identify all steps which shouldb e followedto replace a non-local query by a semantically similar local one.