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

by (Editors: ) [BibTex of ]

News

AKSW Colloquium, 23.01.2017, Automatic Mappings of Tables to Knowledge Graphs and Open Table Extraction ( 2017-01-20T14:02:35+01:00 by Ivan Ermilov)

2017-01-20T14:02:35+01:00 by Ivan Ermilov

Automatic Mappings of Tables to Knowledge Graphs and Open Table Extraction On the upcoming colloquium on 23.01. Read more about "AKSW Colloquium, 23.01.2017, Automatic Mappings of Tables to Knowledge Graphs and Open Table Extraction"

PRESS RELEASE: “HOBBIT so far.” is now available ( 2017-01-09T14:22:29+01:00 by Sandra Bartsch)

2017-01-09T14:22:29+01:00 by Sandra Bartsch

The latest release informs about the conferences our team attended in 2016 as well as about the published blogposts. Read more about "PRESS RELEASE: “HOBBIT so far.” is now available"

4th Big Data Europe Plenary at Leipzig University ( 2016-12-16T14:33:41+01:00 by Sandra Bartsch)

2016-12-16T14:33:41+01:00 by Sandra Bartsch

The meeting, hosted by our partner InfAI e. V., took place on the 14th to the 15th of December at the University of Leipzig. Read more about "4th Big Data Europe Plenary at Leipzig University"

SANSA 0.1 (Semantic Analytics Stack) Released ( 2016-12-09T15:41:04+01:00 by Dr. Jens Lehmann)

2016-12-09T15:41:04+01:00 by Dr. Jens Lehmann

Dear all, The Smart Data Analytics group /AKSW are very happy to announce SANSA 0.1 – the initial release of the Scalable Semantic Analytics Stack. Read more about "SANSA 0.1 (Semantic Analytics Stack) Released"

AKSW wins award for Best Resources Paper at ISWC 2016 in Japan ( 2016-12-09T15:05:00+01:00 by Sandra Bartsch)

2016-12-09T15:05:00+01:00 by Sandra Bartsch

Our paper, “LODStats: The Data Web Census Dataset”, won the award for Best Resources Paper at the recent conference in Kobe/Japan, which was the premier international forum for Semantic Web and Linked Data Community. Read more about "AKSW wins award for Best Resources Paper at ISWC 2016 in Japan"