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.

Project Team

Publications

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News

ASKW Colloquium, 24 August, 3pm, Lucene, SOLR, FEASIBLE ( 2015-08-24T13:40:58+02:00 by Dr. Amrapali Zaveri)

2015-08-24T13:40:58+02:00 by Dr. Amrapali Zaveri

In this colloquium, first, Kay Müller and Nilesh Chakraborty will give an overview of Lucene and SOLR and how they can be used in information retrieval scenarios, along with a short peek into ElasticSearch, introducing a few recent features, their … Continue reading → Read more about "ASKW Colloquium, 24 August, 3pm, Lucene, SOLR, FEASIBLE"

AKSW has 10 accepted publications in Semantics’2015 conference ( 2015-08-18T13:37:02+02:00 by Ivan Ermilov)

2015-08-18T13:37:02+02:00 by Ivan Ermilov

The Semantics‘2015 conference will take place in Vienna, Austria on September 15-17, 2015. AKSW is happy to announce 10 accepted publications: 6 for research track and 4 for demos/posters track. Read more about "AKSW has 10 accepted publications in Semantics’2015 conference"

AKSW Colloquium, 17-08-2015, Relational Machine Learning for Knowledge Graphs, Zoo Keeper, Apache Mesos ( 2015-08-17T10:58:54+02:00 by Patrick Westphal)

2015-08-17T10:58:54+02:00 by Patrick Westphal

Relational Machine Learning for Knowledge Graphs In this colloquium Patrick Westphal will present the paper “A Review of Relational Machine Learning for Knowledge Graphs” by Nickel, Murphy, Tresp and Gabrilovich. Read more about "AKSW Colloquium, 17-08-2015, Relational Machine Learning for Knowledge Graphs, Zoo Keeper, Apache Mesos"

18 AKSW Papers at ISWC 2015 ( 2015-08-12T03:16:15+02:00 by Muhammad Saleem)

2015-08-12T03:16:15+02:00 by Muhammad Saleem

We are very pleased to announce that AKSW will be presenting 18 papers in the upcoming International Semantic Web Conference (ISWC) 2015. Read more about "18 AKSW Papers at ISWC 2015"

Michael Röder at AKSW Colloquium, Monday, 10th August 2015, 3pm ( 2015-08-06T14:17:57+02:00 Michael Roeder)

2015-08-06T14:17:57+02:00 Michael Roeder

Crawling the Linked Open Data Cloud by Michael Röder In the recent years the Linked Open Data Cloud matured to support various applications, e.g., question answering, knowledge inference or database enrichment. Read more about "Michael Röder at AKSW Colloquium, Monday, 10th August 2015, 3pm"