Sparqlify: a SPARQL-SQL rewriter

Sparqlify is a SPARQL-SQL rewriter that enables one to define RDF views on relational databases and query them with SPARQL. It is currently in alpha state and powers the Linked-Data Interface of the LinkedGeoData Server – i.e. it provides access to billions of virtual triples from the OpenStreetMap database.

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Key Features

  • A novel syntax for view definitions inspired by SQL's CREATE VIEW statement. We believe this to lower the learning curve for defining RDB-RDF mappings.
  • A query is rewritten into a single SQL statement, giving all control over query planning to the underlying database system.
  • Support of geo-spatial functions: In general, Sparqlify supports mapping custom SPARQL functions to relational ones. Some mappings for PostGIS are already provided (e.g. intersection with polygons).

Limitations

Please be aware that Sparqlify is currently in alpha state and the following limitations hold:

  • For the moment, only the PostgreSQL database system is supported.
  • Only a subset of SPARQL 1.0 + Sub-Queries is supported: For instance, the implementation of aggregate functions including COUNT is still pending.
  • Support for Sparql 1.1 property paths is very unlikely in the near future.

Publications

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News

AKSW Colloquium, 05.09.2016. LOD Cloud Statistics, OpenAccess at Leipzig University. ( 2016-08-31T11:23:10+02:00 by Ivan Ermilov)

2016-08-31T11:23:10+02:00 by Ivan Ermilov

On the upcoming Monday (05.09.2016), AKSW group will discuss topics related to Semantic Web and LOD Cloud Statistics. Also, we will have invited speaker from University of Leipzig Library (UBL) Dr. Astrid Vieler talking about OpenAccess at Leipzig University. Read more about "AKSW Colloquium, 05.09.2016. LOD Cloud Statistics, OpenAccess at Leipzig University."

AKSW Colloquium, 15th August, 3pm, RDF query relaxation ( 2016-08-10T11:03:58+02:00 Michael Roeder)

2016-08-10T11:03:58+02:00 Michael Roeder

On the 15th of August at 3 PM, Michael Röder will present the paper “RDF Query Relaxation Strategies Based on Failure Causes” of Fokou et al. in P702. Read more about "AKSW Colloquium, 15th August, 3pm, RDF query relaxation"

Article accepted in Journal of Web Semantics ( 2016-08-02T09:54:24+02:00 by Lorenz Bühmann)

2016-08-02T09:54:24+02:00 by Lorenz Bühmann

We are happy to announce that the article “DL-Learner – A Framework for Inductive Learning on the Semantic Web” by Lorenz Bühmann, Jens Lehmann and Patrick Westphal was accepted for publication in the Journal of Web Semantics: Science, Services and Agents on … Continue reading → Read more about "Article accepted in Journal of Web Semantics"

AKSW Colloquium, 18.07.2016, AEGLE and node2vec ( 2016-07-18T14:56:44+02:00 TommasoSoru)

2016-07-18T14:56:44+02:00 TommasoSoru

On Monday 18.07.2016, Kleanthi Georgala will give her Colloquium presentation for her paper “An Efficient Approach for the Generation of Allen Relations”, that was accepted at the European Conference on Artificial Intelligence (ECAI) 2016. Read more about "AKSW Colloquium, 18.07.2016, AEGLE and node2vec"

AKSW Colloquium, 04.07.2016. Big Data, Code Quality. ( 2016-06-29T12:34:35+02:00 by Ivan Ermilov)

2016-06-29T12:34:35+02:00 by Ivan Ermilov

On the upcoming Monday (04.07.2016), AKSW group will discuss topics related to Semantic Web and Big Data as well as programming languages and code quality. Read more about "AKSW Colloquium, 04.07.2016. Big Data, Code Quality."