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.

Current Team

Publications

by (Editors: ) [BibTex of ]

News

Highlights of the 1st Meetup on Question Answering Systems – Leipzig, November 21st ( 2014-11-24T10:09:09+01:00 by Ali Khalili)

2014-11-24T10:09:09+01:00 by Ali Khalili

On November 21st, AKSW group was hosting the 1st meetup on “Question Answering” (QA) systems. In this meeting, researchers from AKSW/University of Leipzig, CITEC/University of Bielefeld, Fraunhofer IAIS/University of Bon, DERI/National University of Ireland and the University of Passau presented the recent results of their work on QA systems. Read more about "Highlights of the 1st Meetup on Question Answering Systems – Leipzig, November 21st"

Announcing GERBIL: General Entity Annotator Benchmark Framework ( 2014-11-20T10:08:33+01:00 by Ricardo Usbeck)

2014-11-20T10:08:33+01:00 by Ricardo Usbeck

Dear all, We are happy to announce GERBIL – a General Entity Annotation Benchmark Framework, a demo can be found at! With GERBIL, we aim to establish a highly available, easy quotable and liable focal point for Named Entity Recognition and Named Entity Disambiguation (Entity Linking) evaluations: GERBIL provides persistent URLs for experimental settings. Read more about "Announcing GERBIL: General Entity Annotator Benchmark Framework"

@BioASQ challenge gaining momentum ( 2014-11-17T15:29:24+01:00 by Ricardo Usbeck)

2014-11-17T15:29:24+01:00 by Ricardo Usbeck

BioASQ is a series of challenges aiming to bring us closer to the vision of machines that can answer questions of biomedical professionals and researchers. The second BioASQ challenge started in February 2013. It comprised two different tasks: Large-scale biomedical semantic indexing (Task 2a), and biomedical semantic question answering (Task 2b). Read more about "@BioASQ challenge gaining momentum"

AKSW successful at #ISWC2014 ( 2014-10-28T17:03:42+01:00 by Ricardo Usbeck)

2014-10-28T17:03:42+01:00 by Ricardo Usbeck

Dear followers, 9 members of AKSW have been participating at the 13th International Semantic Web Conference (ISWC) at Riva del Garda, Italy. Read more about "AKSW successful at #ISWC2014"

AKSW internal group meeting @ Dessau ( 2014-10-23T02:07:29+02:00 EdgardMarx)

2014-10-23T02:07:29+02:00 EdgardMarx

Recently AKSW members were at the city of Dessau for an internal group meeting. The meeting took place between 8th and 10th of October, in the modern university of architecture of Bauhaus were we also stayed hosted. Bauhaus is located in the city of Dessau, about one hour from Leipzig. Read more about "AKSW internal group meeting @ Dessau"