SQL to XQuery Translation in the AquaLogic Data Services Platform

SQL has long been the standard language for retrieving and manipulating data in relational database systems. XML has become the standard format for data exchange, and XQuery is on its way to becoming the standard language for querying XML data. The BEA AquaLogic Data Services Platform provides a service-oriented, XML-based view of heterogeneous enterprise data sources and allows this view to be queried using XQuery. AquaLogic DSP includes a JDBC driver that connects the old (SQL) world with the new (XML) world via a SQL-to-XQuery translator. This paper outlines the issues related to creating such a driver and details the approach used to translate SQL queries into XQuery expressions. The paper also touches on performance considerations related to handling XML query results in a context where JDBC result sets are the desired output format.