50 likes | 74 Views
Learn how to use the OpenRDF workbench for SPARQL queries, accessing RDF data, storing solutions, and executing advanced queries. Follow the steps provided to explore the platform and discover useful queries.
E N D
OpenRDF & SPARQL Short guide on how to use the STI LOI OpenRDF workbench
About OpenRDF • OpenRDF Sesame is a de-facto standard framework for processing RDF data. This includes parsers, storage solutions (RDF databases a.ka. triplestores), reasoning and querying, using the SPARQL query language. It offers a flexible and easy to use Java API that can be connected to all leading RDF storage solutions. • OpenRDF offers also a Web interface for to create, delete and update Repositories via Browser • Repositories can be either queried with SPARQL via the Web interface and also programmatically via JAVA API. • NOTE: Please be careful, the repository/OpenRDF installation currently is not protected against write operations and Repositories can be deleted by everyone. Do not click on the “modify” operations on the left-hand side of the OpenRDF menu.
HOWTO Query • Go to http://loi.sti2.at/openrdf-workbench and click on the correct Repository (Name: STI) • Once you clicked the repository it is loaded and ready for to be queried • Go to Explore –> Query and you will find a form where enter your queries • Just post the query right under the Prefixes • You can leave the „Action options“ untouched • The SPARQL query result is limited to 100 results per page by default. If you want more results just select a number. • Click on Execute and your SPARQL query will be processed and the result is shown.
SPARQL Queries • Some example SPARQL queries that can be used. The single instances have been uploaded and saved in contexts so every single instance can be queried. The contexts have the following form/ URI: • http://loi.sti2.at/2014/01/[SECTOR]/[NAME] • All available Contexts can be found under http://loi.sti2.at/openrdf-workbench/repositories/STI/contexts • Get all tripels from the STI repository • SELECT * WHERE {?s ?p ?o} • Get all tripels of a certain context • SELECT * FROM <http://loi.sti2.at/2014/01/restaurant/AlfredMillersSchöneck> WHERE {?s ?p ?o} • Find more useful and sophisticated Queries on your own!
Sources and Links • OpenRDF http://www.openrdf.org/