RQL: a declarative query language for RDF
Proceedings of the 11th international conference on World Wide Web
Sesame: A Generic Architecture for Storing and Querying RDF and RDF Schema
ISWC '02 Proceedings of the First International Semantic Web Conference on The Semantic Web
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Foundations of semantic web databases
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
SPARQ2L: towards support for subgraph extraction queries in rdf databases
Proceedings of the 16th international conference on World Wide Web
Survey of graph database models
ACM Computing Surveys (CSUR)
Minimal Deductive Systems for RDF
ESWC '07 Proceedings of the 4th European conference on The Semantic Web: Research and Applications
SPARQLeR: Extended Sparql for Semantic Association Discovery
ESWC '07 Proceedings of the 4th European conference on The Semantic Web: Research and Applications
An Extension of SPARQL for RDFS
Semantic Web, Ontologies and Databases
Semantics and complexity of SPARQL
ISWC'06 Proceedings of the 5th international conference on The Semantic Web
Ranking Approximate Answers to Semantic Web Queries
ESWC 2009 Heraklion Proceedings of the 6th European Semantic Web Conference on The Semantic Web: Research and Applications
Representing, Querying and Transforming Social Networks with RDF/SPARQL
ESWC 2009 Heraklion Proceedings of the 6th European Semantic Web Conference on The Semantic Web: Research and Applications
The Perfect Match: RPL and RDF Rule Languages
RR '09 Proceedings of the 3rd International Conference on Web Reasoning and Rule Systems
Coloring RDF Triples to Capture Provenance
ISWC '09 Proceedings of the 8th International Semantic Web Conference
Modeling Concept Evolution: A Historical Perspective
ER '09 Proceedings of the 28th International Conference on Conceptual Modeling
SPARQL Query Re-writing Using Partonomy Based Transformation Rules
GeoS '09 Proceedings of the 3rd International Conference on GeoSpatial Semantics
Towards a theory of search queries
ACM Transactions on Database Systems (TODS)
Certain answers and rewritings for local regular path queries on graph-structured data
Proceedings of the Fourteenth International Database Engineering & Applications Symposium
nSPARQL: A navigational language for RDF
Web Semantics: Science, Services and Agents on the World Wide Web
SPARQL1.1: new features and friends (OWL2, RIF)
RR'10 Proceedings of the Fourth international conference on Web reasoning and rule systems
A RPL through RDF: expressive navigation in RDF graphs
RR'10 Proceedings of the Fourth international conference on Web reasoning and rule systems
vSPARQL: A view definition language for the semantic web
Journal of Biomedical Informatics
Foundations of Semantic Web databases
Journal of Computer and System Sciences
PoweRGen: A power-law based generator of RDFS schemas
Information Systems
RDFPath: path query processing on large RDF graphs with mapreduce
ESWC'11 Proceedings of the 8th international conference on The Semantic Web
Query languages for graph databases
ACM SIGMOD Record
Datalog-based framework for efficient query answering over fuzzy ontologies
International Journal of Metadata, Semantics and Ontologies
Hi-index | 0.00 |
Navigational features have been largely recognized as fundamental for graph database query languages. This fact has motivated several authors to propose RDF query languages with navigational capabilities. In particular, we have argued in a previous paper that nested regular expressions are appropriate to navigate RDF data, and we have proposed the nSPARQL query language for RDF, that uses nested regular expressions as building blocks. In this paper, we study some of the fundamental properties of nSPARQL concerning expressiveness and complexity of evaluation. Regarding expressiveness, we show that nSPARQL is expressive enough to answer queries considering the semantics of the RDFS vocabulary by directly traversing the input graph. We also show that nesting is necessary to obtain this last result, and we study the expressiveness of the combination of nested regular expressions and SPARQL operators. Regarding complexity of evaluation, we prove that the evaluation of a nested regular expression E over an RDF graph G can be computed in time O (|G |·|E |).