What is RPQ

RDF plays an important role in representing Web resources in a natural and flexible way. As the amount of RDF datasets increasingly growing, storing and querying theses data have attracted the attention of more and more researchers. In this chapter, we first make a review of approaches for query processing of RDF datasets. We categorize existing methods as two classes, those making use of RDBMS to implement the storage and retrieval, and those devising their own native storage schemas. They are called Relational RDF Stores and Native Stores respectively. Secondly, we survey some important extensions of SPARQL, standard query language for RDF, which extend the expressing power of SPARQL to allow more sophisticated language constructs that meet the needs from various application scenarios.