The RDF Data Description Language (RDD)

Abstract

Although the intention of RDF is to provide an open, minimally constraining way for representing information, there exists an increasing number of applications for which guarantees on the structure and values of an RDF data set become desirable if not essential. The RDD language has been designed as a user-friendly tool to specify instance-level constraints that hold in RDF data sets. Making constraints explicit by means of RDDs does not only help in asserting and maintaining data quality, but also opens up new optimization opportunities for query engines and, most importantly, makes query formulation a lot easier for users and system developers.

This web pages points to the scientific publications describing the scientific and technical background of the RDD language and contains descriptions and download links to software tools developed in the context of the RDD checker. The RDD language and associated tools are developed as part of the DFG project CORSOS.

Resources

• Publications
  • The technical report Pleasantly Consuming Linked Data with RDF Data Descriptions, including a detailed description of the RDD language, design decisions, its syntax, and its formal semantics
  • A short version of the Technical Report, accepted for publication at the COLD Workshop 2013 [ .pdf ]
• Prototype implementations and technical documentation
  • RDD checker (published under Apache 2 license): first released verion 2.11
  • The RDD checker prototype, implementing the RDD syntax and semantics allowing to check consistency of RDF documents with RDD data description [ binary (.zip) | sources (.zip) ]
  • Documentation of the RDD checker prototype [ .pdf ]
  • Associated JavaDoc of the RDD checker prototype, for developers [ .zip ]
• Example RDD definitions
  • SP2Bench (SPARQL Performance Benchmark) dataset
  • [ sp2bench_baseline.rdd ] : class-centric approach with no global property constraints
  • [ sp2bench_baseline_valid.rdd ] : version of baseline RDD that is valid on 100M triples
  • [ sp2bench_unqualified.rdd ] : unifying PARTIAL and RANGE constraints to global properties section
  • [ sp2bench_unqualified_max.rdd ] : additionally unifying MAX constraints to global properties section
  • [ sp2bench_coverage_cwa.rdd ] : switching from OWA Classes to CWA Classes
  • [ sp2bench_coverage_path.rdd ] : adding global and class specific PATH and SUBPROPERTY constraints

Project Members

• Contact: Georg Lausen (Freiburg University Database Group)
• Peter Fischer (Freiburg University, Web Science)
• Michael Schmidt (previous member of Freiburg University Database Group)
• Alexander Schätzle (Freiburg University Database Group)

References and Related Projects

• W3C RDF(S) Specifications [ RDF | RDF Semantics | RDF Schema ]
• W3C SPARQL Specification [ SPARQL ]