Ontology Web » General

Sparql search engine queries

Working Ontologist — Tue, 26 Oct 2010 08:07:07 +0000

By Pim Keizer

A simple example of some generic sparql queries for use in a search engine.

Search phrase: “Adidas”

Instance match

Select all instances with label "Adidas".

SELECT *

WHERE {

?resource rdfs:label "Adidas" .

}

Find synonyms

Select all classes that are of the same type.

SELECT ?synonyms

WHERE {

?resource rdfs:label "Adidas" .

?resource rdf:type ?type .

?synonyms rdf:type ?type .

}

Find other instances with the same type

Select all instances of the current type.

SELECT ?otherInstances

WHERE {

?resource rdfs:label "Adidas" .

?resource rdf:type ?type .

?objProp rdfs:range ?type .

?otherInstances ?objProp ?resource .

}

Find other classes with the same properties

Select all classes with the same properties as the current instance with :label "Adidas".

SELECT ?otherClasses

WHERE {

?resource rdfs:label "Adidas" .

?resource rdf:type ?type .

?objProp rdfs:range ?type .

?otherInstances ?objProp ?resource .

?otherInstances rdf:type ?otherClasses .

}

Ontology Design Patterns (ODP)

Working Ontologist — Tue, 03 Aug 2010 06:55:56 +0000

Regarding best practice hints, the following two links correspond to two repositories of Ontology Design Patterns:

Mapping relational data to RDF

Working Ontologist — Thu, 06 May 2010 11:26:08 +0000

There has been many research in the domain of mapping relational data from databases like MySQL or Oracle to RDF data.

D2R Server - http://www4.wiwiss.fu-berlin.de/bizer/d2r-server/
Publishing information about the Web-based Systems Group @ Freie Universität Berlin. It can be accessed using (1) your plain old web browser (2) Semantic Web browsers (3) SPARQL query clients.
Virtuoso - http://virtuoso.openlinksw.com/
Virtuoso is an innovative enterprise grade server that cost-effectively delivers an unrivaled platform for Data Access, Integration and Management.

XPath function reference

Working Ontologist — Wed, 21 Apr 2010 09:05:32 +0000

New website: www.XPath.nl

On this website a function reference for XPath is found. The option to use the RSS feed makes it possible to place the link in the toolbar of your browser. From there you are always one click away from the information.

Very useful for developers of XSD, XSLT and schematron.

Triple store

Working Ontologist — Tue, 02 Feb 2010 08:52:09 +0000

Creating à triple store based on mysql. From this triple store several websites are feeded.

OWL 2 Web Ontology Language Primer

Working Ontologist — Mon, 14 Dec 2009 15:14:45 +0000

In the W3C Recommendation of 27 October 2009 the OWL 2 Web Ontology Language is presented.

The primer provides an approachable introduction to OWL 2, including orientation for those coming from other disciplines.

Visit W3C

RDF stands for Resource Description Framework

Working Ontologist — Tue, 08 Dec 2009 08:17:57 +0000

RDF is short for Resource Description Framework. RDF is the language for describing resources and contents in the semantic web. In the semantic web RDF is used to describe resources on the web. Resources are addressed by a unique URI. A URI looks like a normal Internet URL.

Look at the following fragment of a RDF file:

xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns="http://example.org/pets#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xml:base="http://example.org/pets">

What is the Semantic Web?

Working Ontologist — Tue, 08 Dec 2009 08:00:39 +0000

Describing things in a way that computer applications can understand it.

The semantic web describes relations between concepts. For example:

A isPartOf B B hasType C C isMemberOf D

Also properties of concepts can be described:

A hasAge X B hasSize X C has Length X

Where in this case X could be of type Integer.

Protege 4.0 released

Working Ontologist — Mon, 07 Dec 2009 13:55:50 +0000

December 3rd Protege 4.0 was released. So, what is new in this version? First of all it supports the OWL 2.0 specification, which is approaching approval. Other new features in this release are: support for editing multiple ontologies, menu drag and drop user interface elements, the ability to import from repositories on the web and more. Anyway, you can download it here.

Using SVN in Eclipse with a proxy

Working Ontologist — Fri, 04 Dec 2009 13:15:06 +0000

Are you getting errors about the “RA layer request failed” and “svn: PROPFIND request failed on ..”, followed by an error about not being able to connect to the SVN server? Well, here is what to do:

Install the latest Subclipse plugin for Eclipse. Read the manual at Subclipse
Set the right proxy settings at the Subversive-config-file (usuallylocated at C:\Documents and Settings\MyUserId\Application Data\Subversion\servers). At the bottom of the file you’ll find http-proxy-host and http-proxy-port. Uncomment these lines and set the right values. Save this file and restart your Eclipse environment.

For me it worked perfectly. Hope this will be useful for you too.