RWTH Aachen University
The semantic Web aims to create a universal medium for the exchange of semantically tagged data. The idea of representing and querying this information by means of directed labelled graphs, i.e., RDF (Resource Description Framework) and SPARQL has been widely accepted by the scientific community. However, even when most current implementations of RDF/SPARQL are based on ad-hoc storage systems, processing complex queries on large data sets incurs a high number of joins, which may slow down performance. In this paper, the authors propose materialized SPARQL queries as indexes on RDF data sets to reduce the number of necessary joins and thus query processing time.