On the Semantics of Heterogeneous Querying of Relational, XML and RDF Data with XSPARQL
Published in: Portuguese Conference on Artificial Intelligence
2011
Abstract
XSPARQL is a transformation and query language that caters for heterogenous sources: in its present status it is possible to transform data between XML and RDF formats due to the integration of the XQuery and SPARQL query languages. In this paper we propose an extension of the XSPARQL language to incorporate data contained in relational databases by integrating a subset of SQL in the syntax of XSPARQL. Exposing data contained in relational databases as RDF is a necessary step towards the realisation of the Semantic Web and Web of Data. We present the syntax of an extension of the XSPARQL language catering for the inclusion of the SQL query language along with the semantics based on the XQuery formal semantics and sketch how this extended XSPARQL language can be used to expose RDB2RDF mappings, as currently being discussed in the W3C RDB2RDF Working Group.