Matches in ScholarlyData for { <https://w3id.org/scholarlydata/inproceedings/iswc2008/paper/research/259> ?p ?o. }
Showing items 1 to 16 of
16
with 100 items per page.
- 259 creator claudio-gutierrez.
- 259 creator jorge-a-perez.
- 259 creator marcelo-arenas.
- 259 type InProceedings.
- 259 label "nSPARQL: A Navigational Language for RDF".
- 259 sameAs 259.
- 259 abstract "It has been largely recognized that navigational capabilities are fundamental for graph databases query languages. However, although RDF is a directed labeled graph data format, the W3C Recommendation query language for RDF, SPARQL, only provides limited navigational functionalities. This has motivated several authors to propose extensions of SPARQL, or alternative query languages, that offer functionalities for navigating RDF data. In particular, we argued in [6] that nested regular expressions are appropriate to overcome this limitation, and we proposed a query language called nSPARQL that extends SPARQL with this type of expressions. In this paper, we continue with the investigation of nSPARQL. First, we show that nested regular expressions can be evaluated efficiently; if the appropriate data structure is used to store RDF graphs, then the evaluation of a nested regular expression E over an RDF graph G can be computed in time O(|G|*|E|). Second, as RDF graphs may contain RDFS vocabulary, we study how the navigational capabilities of nSPARQL can be used to evaluate queries according to the predefined semantics of RDFS. Evaluating queries which involve the RDFS vocabulary is challenging, and there is not yet consensus in the Semantic Web community on how to define a query language for RDFS. In this respect, we show that nSPARQL is expressive enough to answer SPARQL queries involving RDFS vocabulary by directly traversing the input RDF graphs. Moreover, we also prove that nesting is necessary to obtain this result. Namely, we show that, in general, regular expressions alone cannot be used to obtain the answer of a SPARQL query involving RDFS vocabulary.".
- 259 hasAuthorList authorList.
- 259 hasTopic Semantic_Web.
- 259 isPartOf proceedings.
- 259 keyword "RDF".
- 259 keyword "RDFS".
- 259 keyword "SPARQL".
- 259 keyword "navigating RDF data".
- 259 keyword "regular expressions".
- 259 title "nSPARQL: A Navigational Language for RDF".