Translation of Relational and Non-relational Databases into RDF with xR2RML

Franck Michel, Loïc Djimenou, Catherine Faron-Zucker, Johan Montagnat


With the growing amount of data being continuously produced, it is crucial to come up with solutions to expose data from ever more heterogeneous databases (e.g. NoSQL systems) as linked data. In this paper we present xR2RML, a language designed to describe the mapping of various types of databases to RDF. xR2RML flexibly adapts to heterogeneous query languages and data models while remaining free from any specific language or syntax. It extends R2RML, the W3C recommendation for the mapping of relational databases to RDF, and relies on RML for the handling of various data representation formats. We analyse data models of several modern databases as well as the format in which query results are returned, and we show that xR2RML can translate any data element within such results into RDF, relying on existing languages such as XPath and JSONPath if needed. We illustrate some features of xR2RML such as the generation of RDF collections and containers, and the ability to deal with mixed content.


  1. Acosta, M., Vidal, M., Lampo, T., Castillo, J., and Ruckhaus, E. (2011). ANAPSID: an adaptive query processing engine for SPARQL endpoints. In Proc. of ISWC'11, pages 18-34.
  2. Arenas, M., Bertails, A., Prud'hommeaux, E., and Sequeda, J. (2012). A direct mapping of relational data to RDF.
  3. Bikakis, N., Tsinaraki, C., Stavrakantonakis, I., Gioldasis, N., and Christodoulakis, S. (2013). The SPARQL2XQuery interoperability framework. CoRR, abs/1311.0536.
  4. Bischof, S., Decker, S., Krennwallner, T., Lopes, N., and Polleres, A. (2012). Mapping between RDF and XML with XSPARQL. Journal on Data Semantics, 1(3):147-185.
  5. Breitling, F. (2009). A standard transformation from XML to RDF via XSLT. Astronomical Notes, 330:755.
  6. Das, S., Sundara, S., and Cyganiak, R. (2012). R2RML: RDB to RDF mapping language.
  7. de Medeiros, L. F., Priyatna, F., and Corcho, O. (2015). MIRROR: Automatic R2RML mapping generation from relational databases. In Subm. to ICWE 2015.
  8. Dimou, A., Sande, M. V., Slepicka, J., Szekely, P., Mannens, E., Knoblock, C., and Walle, R. V. d. (2014a). Mapping hierarchical sources into RDF using the RML mapping language. In Proc. of ICSC'2014, pages 151-158. IEEE.
  9. Dimou, A., Vander Sande, M., Colpaert, P., Verborgh, R., Mannens, E., and Van de Walle, R. (2014b). RML: A generic language for integrated RDF mappings of heterogeneous data. In Proc. of the 7th LDOW workshop.
  10. Fagin, R., Haas, L. M., Hernndez, M., Miller, R. J., Popa, L., and Velegrakis, Y. (2009). Clio: Schema mapping creation and data exchange. In Conceptual Modeling: Foundations and App., pages 198-236. Springer.
  11. Fennell, P. (2014). Schematron - more useful than you'd thought. In Proc. of the XML London 2014 Conference, pages 103-112.
  12. Field, L., Suhr, S., Ison, J., Wittenburg, P., Los, W., Broeder, D., Hardisty, A., Repo, S., and Jenkinson, A. (2013). Realising the full potential of research data: common challenges in data management, sharing and integration across scientific disciplines.
  13. Floratou, A., Minhas, U. F., and Ozcan, F. (2014). Sql-onhadoop: Full circle back to shared-nothing database architectures. Proc. of the VLDB Endowment, 7(12).
  14. Gaignard, A. (2013). Distributed knowledge sharing and production through collaborative e-science platforms. PhD thesis.
  15. Gajendran, S. K. (2013). A survey on NoSQL databases (technical report).
  16. He, B., Patel, M., Zhang, Z., and Chang, K. C.-C. (2007). Accessing the deep web. Communications of the ACM, 50(5):94-101.
  17. Hecht, R. and Jablonski, S. (2011). NoSQL evaluation: A use case oriented survey. In Proc. of CSC'2011, pages 336-341. IEEE Computer Society.
  18. Knoblock, C. A., Szekely, P., Ambite, J. L., Goel, A., Gupta, S., Lerman, K., Muslea, M., Taheriyan, M., and Mallick, P. (2012). Semi-automatically mapping structured sources into the semantic web. In Proc. of ESWC'2012, pages 375-390. Springer.
  19. Kolev, B., Valduriez, P., Jimenez-Peris, R., Martìnez-Bazan, N., and Pereira, J. (2014). CloudMdsQL: Querying heterogeneous cloud data stores with a common language. In Proc. of the BDA'2014 Conference.
  20. Langegger, A. and Wöss, W. (2009). XLWrap - querying and integrating arbitrary spreadsheets with SPARQL. In Proc. of ISWC'2009.
  21. Melton, J., Michels, J. E., Josifovski, V., Kulkarni, K., and Schwarz, P. (2002). SQL/MED: a status report. ACM SIGMOD Record, 31(3):81-89.
  22. Michel, F., Djimenou, L., Faron-Zucker, C., and Montagnat, J. (2014a). xR2RML: Relational and non-relational databases to RDF mapping language. Research report. ISRN I3S/RR 2014-04-FR v3.
  23. Michel, F., Montagnat, J., and Faron-Zucker, C. (2014b). A survey of RDB to RDF translation approaches and tools. Research report. ISRN I3S/RR 2013-04-FR.
  24. Ong, K. W., Papakonstantinou, Y., and Vernoux, R. (2014). The SQL++ unifying semi-structured query language, and an expressiveness benchmark of SQL-on-Hadoop, NoSQL and NewSQL databases (submitted). CoRR, abs/1405.3631.
  25. Priyatna, F., Corcho, O., and Sequeda, J. (2014). Formalisation and experiences of R2RML-based SPARQL to SQL query translation using Morph. In Proc. of WWW'2014.
  26. Roth, M. T. and Schwartz, P. (1997). Don't scrap it, wrap it! A wrapper architecture for legacy data sources. In Proc. of VLDB'1997, pages 266-275.
  27. Scharffe, F., Atemezing, G., Troncy, R., Gandon, F., Villata, S., Bucher, B., Hamdi, F., Bihanic, L., Képéklian, G., Cotton, F., and others (2012). Enabling linked data publication with the Datalift platform. In Proc. of the AAAI workshop on semantic cities.
  28. Schwarte, A., Haase, P., Hose, K., Schenkel, R., and Schmidt, M. (2011). FedX: Optimization techniques for federated query processing on linked data. In Proc. of ISWC'11, pages 601-616.
  29. Sequeda, J., Tirmizi, S. H., Corcho, s., and Miranker, D. P. (2011). Survey of directly mapping SQL databases to the semantic web. Knowledge Eng. Review, 26(4):445-486.
  30. Sequeda, J. F. and Miranker, D. P. (2013). Ultrawrap: SPARQL execution on relational data. Web Semantics: Sc., Serv. and Agents on the WWW, 22:19-39.
  31. Shvaiko, P. and Euzenat, J. (2005). A survey of schemabased matching approaches. In Journal on Data Semantics IV, pages 146-171. Springer.
  32. Spanos, D.-E., Stavrou, P., and Mitrou, N. (2012). Bringing relational databases into the semantic web: A survey. Semantic Web Journal, 3(2):169-209.

Paper Citation

in Harvard Style

Michel F., Djimenou L., Faron-Zucker C. and Montagnat J. (2015). Translation of Relational and Non-relational Databases into RDF with xR2RML . In Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST, ISBN 978-989-758-106-9, pages 443-454. DOI: 10.5220/0005448304430454

in Bibtex Style

author={Franck Michel and Loïc Djimenou and Catherine Faron-Zucker and Johan Montagnat},
title={Translation of Relational and Non-relational Databases into RDF with xR2RML},
booktitle={Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST,},

in EndNote Style

JO - Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST,
TI - Translation of Relational and Non-relational Databases into RDF with xR2RML
SN - 978-989-758-106-9
AU - Michel F.
AU - Djimenou L.
AU - Faron-Zucker C.
AU - Montagnat J.
PY - 2015
SP - 443
EP - 454
DO - 10.5220/0005448304430454