Querying Data from Distributed Heterogeneous Database Systems through Web Services

Nicholas L. Carroll, Web Engineering Group, School of Electrical and Information Engineering, The University of Sydney. Email: ncarroll@ee.usyd.edu.au

Rafael A. Calvo, Web Engineering Group, School of Electrical and Information Engineering, The University of Sydney. Email: rafa@ee.usyd.edu.au

Keywords

Web services, interoperability, distributed computing, database system.

Abstract

In this paper we study the integration of Web services in an object-relational database system. This allows a database to import data from live data feeds or remote heterogeneous database systems on demand. We first describe how we have added a SOAP interface to the PostgreSQL database system, implemented as a user-defined function that allows developers to make service calls from within the database. Secondly, we show that SQL can also be used to query data provided by Web services, which introduces a novel way of accessing and using Web services in a database-driven web application. Finally, we compare the performance of two architectures for consuming Web services with a benchmarking procedure using the Google Web service API.