SPARQL is the W3C standard for querying RDF data, but it mostly provides means for querying simple RDF graphs only, whereas querying with respect to RDF Schema or other entailment regimes is left outside the current specification (NOTE: This article was written prior to SPARQL 1.1). In this paper, the authors argue that SPARQL faces certain unwanted ramifications when querying ontologies in conjunction with RDF datasets that comprise multiple named graphs, and they provide an extension for SPARQL that remedies these effects. Moreover, since RDF Schema inference has a close relationship with logic rules, the authors generalize their approach to select a custom ruleset for specifying inferences to be taken into account in a SPARQL query.
Keywords: SPARQL, RDF Schema, Datalog, SQL
Author: Polleres, Axel
Date created: 2009-01-01 05:00:00.000
Time required: P30M
Educational use: instruction
Educational audience: student
Interactivity type: expositive