A comparative study of various variants of SPARQL in semantic web

SPARQL is the W3C recommended querying language for RDF and OWL databases. It is designed for use at the global data on the Web, and thus enables queries over strewn data sources, independent of format. Due to unanticipated data sources, it is easier to extend the SPARQL queries. This paper briefly describes about the variants of SPARQL which have been designed to enhance its capabilities in various domains. The present list of variants includes SPARQL-DL, nSPARQL, iSPARQL, SPARQL++, PSPARQL, and SPARQL-ST. In this paper we present a comparative study between these variants on the basis of their performance, expressiveness, ease of implementation, inter and backward compatibility.