Local Query Generation for Distributed XQuery Queries

Abstract

XML view is proposed to integrate between XML data and heterogeneous data over distributed environment and global XML view is used to search distributed heterogeneous data. Distributed XQuery queries based on a global XML view can search heterogeneous data seamlessly, being distributed in the local systems. One of the basic and simple methods to process distributed SQL queries is that generates local SQL queries for processing a distributed SQL query and constructs the result of the distributed query from the results of the local queries. Therefore, it is natural to consider how the method for distributed SQL queries can be applied to processing XQuery queries. However, the syntax of XQuery differs from SQL because the XQuery contains some special expressions like FOR clauses for querying to semi-structured data. Therefore, this paper defines some problems to generate local XQuery queries for processing distributed XQuery queries and proposes a method for generating local XQuery queries considered these problems. We also implement a distributed XQuery query processor using our method.