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| [[has overview::A triple store is a convenient method for the storage and retrieval of Resource Description Framework Schema (RDFS) and statements in a relational database. RDF(S) is the underlying representation of semantic data in SMW and SMW+.]] |
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Overview
A triple store is a convenient method for the storage and retrieval of Resource Description Framework Schema (RDFS) and statements in a relational database. RDF(S) is the underlying representation of semantic data in SMW and SMW+. The final version was published by the World-Wide Web Consortium (W3C) in February 2004. RDF(S) is a standardized language for knowledge representation and lightweight ontologies. Many RDF(S) components are included in the more expressive Web Ontology Language (OWL).
The RDF-triples
The SMW knowledge base corresponds to a set of RDF-triples. This means that statements about the (web) resources are made in the form of subject-predicate-object expressions as shown in Fig. 1.
A collection of RDF statements basically represents a labelled and directed multi-graph.
This RDF graph represents machine-readable statements about one individual called ‘Daniel’. It indicates that there is a living being and more precisely, a person called Daniel Hansch. RDF takes the data elements, e. g. Person, which are identified by URIs and makes statements about the relationship between one element and the other. The wiki lets you model these three statements as follows.
Write the following on the page 'Daniel':
[[hasName::Daniel Hansch]] [[Category:Person]]
Write the following on the page 'Person':
[[Category:Living Being]]
You can use the following concepts to create a lightweight ontology:
Classes
- Class: lets you declare a resource as a resource class in connection with the type to create instances.
- Resource: each entity in a RDF-Model is this class’es instance.
- Property: a class for attributes, subclass of Resource.
- Literal: a class for literals, e. g. strings
Properties
- subClassOf: lets you declare class hierarchies.
- subPropertyOf: lets you declare property hierarchies.
- domain: lets you declare the class of the subject in a triple using this property as predicate.
- range: lets you declares the class or datatype of the object in a triple using this property as a predicate.
The chief RDF graphs query language is SPARQL which is an acronym that stands for Simple Protocol and RDF Query Language
The SMW+ Triple Stores
SMW+ provides connectors to the following triple stores:
The OntoBroker Triple Store Connector
The Ontobroker Triplestore Connector contains 'Ontobroker' and a connector that connects the Ontobroker to SMW+. OntoBroker is a highly scalable and industry-proven RDF triplestore, query and inference engine that is provided by ontoprise. With a triplestore-enabled SMW+, you can query the semantic data directly within the wiki or remotely using SPARQL queries.
SPARQL is a standard RDF query language that is more powerful than the original wiki query language. It supports the searching of complex graph patterns and enhanced data filtering.
Apart from SPARQL support, the Ontobroker also supports RDF(S) and rule reasoning with its in-built inference engine.
The Triplestore Connector comes with a ready-to-use Windows installer.
Please contact ontoprise,if you wish to download the Ontobroker Triple Store Connector. Get into the ontoprise shop for further information.
The Jena Triple Store Connector
The Basic Triplestore Connector contains the Jena Triplestore and a connector that connects the Triplestore to SMW+. Jena is an open-source framework for managing and handling semantic data.
With a triplestore-enabled SMW+ you can query the semantic data directly within the wiki or remotely using SPARQL queries.
SPARQL is a standard RDF query language that is more powerful than the original wiki query language. It lets you search for complex graph patterns and enhanced data filtering. Apart from SPARQL support, Jena also supports RDF(S) and OWL reasoning with its in-built inference engine. The Triplestore Connector comes with a ready-to-use Windows installer.
One may download the Jena Triple Store Connector for free from SourceForge or from the Ontoprise webshop
- Copyright © 2009 Ontoprise GmbH.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the article "GNU Free Documentation License".
