http://www.w3.org/ -- 15 januari 2008 -- W3C heeft vandaag de publicatie van SPARQL bekendgemaakt. SPARQL is de voornaamste standaard om gegevens op het Semantisch Web open te stellen. Met de zoektechnologie van SPARQL (spreek uit: "sparkel") kunnen mensen zich concentreren op wat zij willen weten in plaats van op de databasetechnologie of het databaseformat die onder de motorkap worden gebruikt om de gegevens op te slaan. Omdat zoekopdrachten van SPARQL 'doeleinden van hoog niveau weergeven', is het makkelijker om ze tot onvoorziene databanken uit te breiden of ze naar nieuwe applicaties over te brengen.
"Proberen het Semantisch Web te gebruiken zonder SPARQL is hetzelde als proberen een relationele database te gebruiken zonder SQL," verklaarde Tim Berners-Lee, directeur van W3C. "SPARQL maakt het mogelijk om in het wilde weg op het Web informatie op te vragen uit databases en andere bronnen van wat voor soort ook."
Er zijn al 14 implementaties van SPARQL, waarvan veel open source.
Many successful query languages exist, including standards such as SQL and XQuery. These were primarily designed for queries limited to a single product, format, type of information, or local data store. Traditionally, it has been necessary to formulate the same high-level query differently depending on application or the specific arrangement chosen for the relational database. And when querying multiple data sources it has been necessary to write logic to merge the results. These limitations have imposed higher developer costs and created barriers to incorporating new data sources.
The goal of the Semantic Web is to enable people to share, merge, and reuse data globally. SPARQL is designed for use at the scale of the Web, and thus enables queries over distributed data sources, independent of format. Creating a single query across diverse data stores is easier than having to create multiple queries; it also costs less and provides richer results.
Because SPARQL has no tie to a specific database format, it can be used to take advantage of the tidal wave of Web 2.0 data and mash it up with other Semantic Web resources. Furthermore, because disparate data sources may not have the same 'shape' or share the same properties, SPARQL is designed to query non-uniform data.
The combination of the SPARQL query language and protocol creates a Web service in its purest sense; running on top of HTTP or SOAP, it provides a standard Web service for anything which asks a question.
"SPARQL's focus on querying the data models saves time for developers; there's no need for a host of little Web services to retrieve different aspects of the state of a system," explained Lee Feigenbaum, Chair of the RDF Data Access Working Group. "This allows the user of the SPARQL endpoint to ask any question -- it is as though they could design their own interface instead of having to work with a limited set of fixed services."
The SPARQL specification defines a query language and a protocol and works with the other core Semantic Web technologies from W3C: Resource Description Framework (RDF) for representing data; RDF Schema; Web Ontology Language (OWL) for building vocabularies; and Gleaning Resource Descriptions from Dialects of Languages (GRDDL), for automatically extracting Semantic Web data from documents. SPARQL also makes use of other W3C standards found in Web services implementations, such as Web Services Description Language (WSDL).
W3C RDF Data Access Working Group produced the three SPARQL Recommendations issued today: the SPARQL Query Language for RDF, The SPARQL Protocol for RDF, and the SPARQL Query Results XML Format. The Working Group includes invited experts and participants from Agfa-Gevaert N. V.; Asemantics S.R.L.; Clark & Parsia LLC; Cleveland Clinic; Eindhoven University of Technology; Free University of Bozen-Bolzano; Garlik; HP; IBM Corporation; Matsushita Electric Industrial Co., Ltd. (MEI); Nippon Telegraph & Telephone Corp. (NTT); OpenLink Software; Oracle Corporation; and Profium, Ltd. The SPARQL Testimonials page contains statements of support and commitments to implement the new Recommendations.
W3C blijft de relatie tussen het Semantisch Web en traditionele databases verbeteren; zie het report from the W3C Workshop on RDF Access to Relational Databases from October 2007.