Querry Processing in Multidatabase Systems
Tadeusz Morzy, Zbyszko Królikowski, Mikołaj Morzy · Bulletin of the Polish Academy of Sciences Technical Sciences · 2001
Query processing in multidatabase systems differs significantly from the processing in distributed database systems. The main differences are: the lack of control over query execution in local databases and the inaccessibility of information about processing costs of the execution of queries in component databases. In this paper we present the architecture of a multidatabase system. We introduce the formal definition of query execution model. We also present the comparison of query optimization techniques in multidatabase systems. We analyse some query language concepts for semistructured data querying. We conclude with the survey of results and a future research agenda for query optimization in multidatabase systems.