Formal aspects of querying RDF databases

Abstract

We study formal aspects of querying databases containing RDF data. We present a formal definition of a query language for RDF and compare it with other proposals. Our language is intended to make it easy to formalize and prove results about its properties. We study novel features of query languages derived from the presence of blank nodes and reification. Finally we provide complexity results for query processing, static optimization of queries, and redundancy elimination in answers.