CORNER: A Completeness Reasoner for SPARQL Queries Over RDF Data Sources
With the increased availability of data on the Semantic Web, the question whether data sources offer data of appropriate quality for a given purpose becomes an issue. With CORNER, we specifically address the data quality aspect of completeness. CORNER supports SPARQL BGP queries and can take RDFS ontologies into account in its analysis. If a query can only be answered completely by a combination of sources, CORNER rewrites the original query into one with SPARQL SERVICE calls, which assigns each query part to a suitable source, and executes it over those sources. CORNER builds upon previous work by Darari et al.  and is implemented using standard Semantic Web frameworks.
KeywordsData quality Data completeness Query completeness SPARQL
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