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).


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.


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AKSW Colloquium, 17.10.2016, Version Control for RDF Triple Stores + NEED4Tweet ( 2016-10-17T09:55:50+02:00 by Marvin Frommhold)

2016-10-17T09:55:50+02:00 by Marvin Frommhold

In the upcoming Colloquium, October the 17th at 3 PM, two papers will be presented: Version Control for RDF Triple Stores Marvin Frommhold will discuss the paper “Version Control for RDF Triple Stores” by Steve Cassidy and James Ballantine which forms the foundation … Continue reading → Read more about "AKSW Colloquium, 17.10.2016, Version Control for RDF Triple Stores + NEED4Tweet"

LIMES 1.0.0 Released ( 2016-10-14T11:38:31+02:00 by Kleanthi Georgala)

2016-10-14T11:38:31+02:00 by Kleanthi Georgala

Dear all, the LIMES Dev team is happy to announce LIMES 1.0.0. LIMES, the Link Discovery Framework for Metric Spaces, is a link discovery framework for the Web of Data. Read more about "LIMES 1.0.0 Released"

DL-Learner 1.3 (Supervised Structured Machine Learning Framework) Released ( 2016-10-11T21:41:00+02:00 by Dr. Jens Lehmann)

2016-10-11T21:41:00+02:00 by Dr. Jens Lehmann

Dear all, the Smart Data Analytics group at AKSW is happy to announce DL-Learner 1.3. DL-Learner is a framework containing algorithms for supervised machine learning in RDF and OWL. Read more about "DL-Learner 1.3 (Supervised Structured Machine Learning Framework) Released"

OntoWiki 1.0.0 released ( 2016-10-05T16:50:05+02:00 by Natanael Arndt)

2016-10-05T16:50:05+02:00 by Natanael Arndt

Dear Semantic Web and Linked Data Community, we are proud to finally announce the releases of OntoWiki 1.0.0 and the underlying Erfurt Framework in version 1.8.0. Read more about "OntoWiki 1.0.0 released"

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."