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

AKSW Colloquium, 27-04-2015, Ontotext’s RDF database-as-a-service (DBaaS) via Self-Service Semantic Suite (S4) platform via & Knowledge-Based Trust ( 2015-04-23T17:21:00+02:00 JoergUnbehauen)

2015-04-23T17:21:00+02:00 JoergUnbehauen

This colloquium features two talks. First the Self-Service Semantic Suite (S4) platform is presented by Marin Dimitrov (Ontotext), followed up by Jörg Unbehauens report on Googles effort on using factual correctness as a ranking factor. Read more about "AKSW Colloquium, 27-04-2015, Ontotext’s RDF database-as-a-service (DBaaS) via Self-Service Semantic Suite (S4) platform via & Knowledge-Based Trust"

Talk by Kleanthi Georgala ( 2015-04-22T22:48:27+02:00 by Dr. Amrapali Zaveri)

2015-04-22T22:48:27+02:00 by Dr. Amrapali Zaveri

Last week on Friday, 17th April, Kleanthi Georgala visited AKSW and gave a talk entitled “Traces Through Time: Probabilistic Record Linkage – Medieval and Early Modern”. More information below. Read more about "Talk by Kleanthi Georgala"

SAKE Projekt website goes live ( 2015-04-22T11:50:43+02:00 by Simon Bin)

2015-04-22T11:50:43+02:00 by Simon Bin

Hi all! The project website for the BMWi funded Smart Data Web Project “SAKE” is now on-line at www.sake-projekt.de. Read more about "SAKE Projekt website goes live"

AKSW Colloquium, 20-04-2015, OWL/DL approaches to improve POS tagging ( 2015-04-20T08:21:00+02:00 Markus Ackermann)

2015-04-20T08:21:00+02:00 Markus Ackermann

In this colloquium Markus Ackermann will touch on the ‘linguistic gap‘ of recent POS tagging endeavours (as perceived by C. Manning, [1]). Read more about "AKSW Colloquium, 20-04-2015, OWL/DL approaches to improve POS tagging"

AKSW Colloquium, 13-04-2015, Effective Caching Techniques for Accelerating Pattern Matching Queries ( 2015-04-13T11:51:58+02:00 by Claus Stadler)

2015-04-13T11:51:58+02:00 by Claus Stadler

In this colloquium, Claus Stadler will present the paper Effective Caching Techniques for Accelerating Pattern Matching Queries by Arash Fard, Satya Manda, Lakshmish Ramaswamy, and John A. Miller. Read more about "AKSW Colloquium, 13-04-2015, Effective Caching Techniques for Accelerating Pattern Matching Queries"