Navigational queries as property path queries employing the Kleene star operator
Ioannis A. Papadakis, Spyridon Kazanas, Michalis Stefanidakis · 2016
In the context of SPARQL, queries could be seen as patterns that are matched against an RDF graph. Until recently, it was not possible to create a pattern without specifying the exact path of the underlying graph (in terms of real data and/or variables) that would match against the graph. The advent of SPARQL 1.1 introduced property paths as a new graph matching paradigm that allows the employment of Kleene star * (and it's variant +) unary operators to build SPARQL queries that are agnostic of the underlying RDF graph structure. In this paper, we propose a generic SPARQL rewriting method that facilitates the execution of property path queries employing Kleene star * (and it's variant +) unary operators. This method is further extended through the employment of the RDF-Type Summary graph in an effort to reduce query execution time. The proposed approach is accordingly evaluated in terms of scalability with promising results.