Enabling Fine-Grained RDF Data Completeness Assessment

Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9671)


Nowadays, more and more RDF data is becoming available on the Semantic Web. While the Semantic Web is generally incomplete by nature, on certain topics, it already contains complete information and thus, queries may return all answers that exist in reality. In this paper we develop a technique to check query completeness based on RDF data annotated with completeness information, taking into account data-specific inferences that lead to an inference problem which is \(\varPi ^P_2\)-complete. We then identify a practically relevant fragment of completeness information, suitable for crowdsourced, entity-centric RDF data sources such as Wikidata, for which we develop an indexing technique that allows to scale completeness reasoning to Wikidata-scale data sources. We verify the applicability of our framework using Wikidata and develop COOL-WD, a completeness tool for Wikidata, used to annotate Wikidata with completeness statements and reason about the completeness of query answers over Wikidata. The tool is available at


RDF Data completeness SPARQL Query completeness Wikidata 



We would like to thank Sebastian Rudolph for his feedback on an earlier version of this paper. The research was supported by the projects “CANDy: Completeness-Aware Querying and Navigation on the Web of Data” and “TaDaQua - Tangible Data Quality with Object Signatures” of the Free University of Bozen-Bolzano, and “MAGIC: Managing Completeness of Data” of the province of Bozen-Bolzano.


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Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Free University of Bozen-BolzanoBolzanoItaly

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