P2P Schema-Mapping over Network-bound XML Data

The rise in availability of web-based data sources has led to new challenges in data integration systems for obtaining decentralized, wide-scale sharing of data preserving semantics. In this paper we present a framework for integrating heterogeneous XML data sources distributed over a large-scale, highly dynamic network of autonomous nodes.We propose a query reformulation algorithm to combine and query distributed XML databases through a decentralized point-to-point mediation process among the different data sources by using P2P schema mappings.More precisely, our integration model is based on path-to-path mappings, using the XPath language. We demonstrate the utility and scalability of our ideas and algorithms with a detailed set of experiments. Finally, we present our experience implementing the above cited query reformulation algorithm as a Web service within the GDIS system, a service-based grid architecture.We have evaluated GDIS on several real world schemas with promising results.