RWTH Aachen University
When an RDF (Resource Description Framework) graph, representing for instance the specification of ontology, is changed, some applications require the past version to be maintained in addition to the new one. In this paper, the authors present a temporal extension of the SPARQL query language for RDF graphs. The new language is based on a temporal RDF database model employing triple time stamping with temporal elements, which best preserves the scalability property enjoyed by triple storage technologies, especially in a multi-temporal setting. The proposed SPARQL extensions are aimed at embedding several features of the TSQL2 consensual language designed for temporal relational databases.