Query Optimization And Processing In Information Integration System

With the development of technology of information integration and the www, people want to get the complete information from distributed and heterogeneity information. One of the main characteristics of information integration is to deal with plentiful requests of query, so, query processing and optimization are very important to information integration system.In this paper, the emphases we researched are query optimization and processing in information integration system based on existing technologies in information integration. In query optimization, we researched the shortage in traditional concept of query containment based on the characteristic of information integration system; we optimized the aggregate of query based on Pseudo containment and decide the sequence of query by the pseudo containment tree of the aggregate.In query processing, we researched mapping rules and sub-query rewrite from local ontology to database. The query language is ontology query language, it is the query language that query in global ontology. From parsing of the single ontology query language, we build a query tree, based on mapping rules that from local ontology to global ontology and from local ontology to data source, used arithmetic of query decomposition and sub-query rewrite, changed the sub-query language to SQL that is correlative to data source at last.In ontology modeling, we used protégé. At last, we analyzed the results in query processing and optimization by typical query example.