Copyright © 2009 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
This document describes SPARQL Service Descriptions, a method for discovering and vocabulary for describing SPARQL services made available via the SPARQL Protocol. Such descriptions are intended to provide a mechanism by which a client or end user can discover information about the SPARQL implementation/service such as supported extension functions and details about the available dataset.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This is the First Public Working Draft of the "SPARQL 1.1 Service Description" specification for review by W3C members and other interested parties.
If you wish to make comments regarding this document, please send them to public-rdf-dawg-comments@w3.org (subscribe, archives)
Implementors should be aware that this specification is not stable. Implementors who are not taking part in the discussions are likely to find the specification changing out from under them in incompatible ways. Vendors interested in implementing this specification before it eventually reaches the Candidate Recommendation stage should join the aforementioned mailing lists and take part in the discussions.
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
The publication of this document by the W3C as a W3C Working Draft does not imply that all of the participants in the W3C SPARQL working group endorse the contents of the specification. Indeed, for any section of the specification, one can usually find many members of the working group or of the W3C as a whole who object strongly to the current text, the existence of the section at all, or the idea that the working group should even spend time discussing the concept of that section.
The W3C SPARQL Working Group is the W3C working group responsible for this specification's progress along the W3C Recommendation track.
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
1 Introduction
2 Accessing Service Descriptions
3 Service Description Vocabulary
3.1 SPARQL Service Description Namespace
3.2 Classes
3.2.1 sd:Service
3.2.2 sd:Language
3.2.3 sd:Function
3.2.4 sd:ScalarFunction
3.2.5 sd:AggregateFunction
3.2.6 sd:EntailmentRegime
3.3 Instances
3.3.1 sd:SPARQLQuery
3.3.2 sd:SPARQLUpdate
3.4 Properties
3.4.1 sd:url
3.4.2 sd:feature
3.4.3 sd:supportedEntailment
3.4.4 sd:extensionFunction
3.4.5 sd:languageExtension
3.4.6 sd:supportedLanguage
3.4.7 sd:datasetDescription
3.4.8 sd:datasetDescriptionURL
4 Example
A References
A.1 Normative References
B CVS History
B.1
SPARQL Service Descriptions are a way of describing the features of a SPARQL service made available via the SPARQL Protocol. This document describes both a method for discovering service descriptions from a specific SPARQL service, and an RDF schema for encoding such descriptions in RDF.
SPARQL services made available via the SPARQL Protocol SHOULD return a service description document at the service URL. This service description SHOULD be made available in an RDF serialization, but MAY also be provided embedded in HTML by RDFa, or other RDF representations by using content negotiation.
The SPARQL Service Description namespace IRI is:
http://www.w3.org/ns/sparql-service-description#
The prefix used in this document for this namespace is sd:.
An instance of sd:Service represents a SPARQL service made available via the SPARQL Protocol.
sd:Service is an instance of rdfs:Class.
An instance of sd:Language represents a subset of the SPARQL language that may be provided by an sd:Service. @@ Better word than "subset" to describe this?
sd:Language is an instance of rdfs:Class.
An instance of sd:ScalarFunction represents an extension function that may be used in a SPARQL FILTER/HAVING clause or a project expression.
sd:ScalarFunction is a subclass of sd:Function.
@@ Need to update list of instances with defined entailment regimes and supported functions.
The service URL of an sd:Service supporting the SparqlQuery interface. @@ this is language from the protocol document. Is it appropriate here?
sd:url is an instance of owl:InverseFunctionalProperty. The rdfs:domain of sd:url is sd:Service.
Releates an instance of sd:Service with a resource representing a supported feature.
The rdfs:domain of sd:feature is sd:Service.
Releates an instance of sd:Service with a resource representing a supported entailment regime for basic graph pattern matching. This property is intended for use when a single entailment regime applies to every graph in the dataset. If different entailment regimes apply to different graphs in the dataset, another property should be used to indicate this fact in the description of the dataset.
sd:supportedEntailment is an rdfs:subPropertyOf sd:feature. The rdfs:domain of sd:supportedEntailment is sd:Service. The rdfs:range of sd:supportedEntailment is sd:EntailmentRegime.
Releates an instance of sd:Service to a function that is supported as either a scalar, value testing function (as described in SPARQL 11.6 @@ old sparql spec reference) or an aggregate function. The rdf:type of the function may be used to indicate which of these function types apply, being either sd:ScalarFunction or sd:AggregateFunction.
sd:extensionFunction is an rdfs:subPropertyOf sd:feature. The rdfs:domain of sd:extensionFunction is sd:Service. The rdfs:range of sd:extensionFunction is sd:Function.
Releates an instance of sd:Service to a resource representing an implemented extension to the SPARQL Query or Update language.
sd:languageExtension is an rdfs:subPropertyOf sd:feature. The rdfs:domain of sd:languageExtension is sd:Service.
Releates an instance of sd:Service to a SPARQL language subset (e.g. Query and Update) that it implements.
sd:supportedLanguage is an rdfs:subPropertyOf sd:feature. The rdfs:domain of sd:supportedLanguage is sd:Service. The rdfs:range of sd:supportedLanguage is sd:Language.
Releates an instance of sd:Service to a description of its available dataset. Depending on the implementation, this may describe the default dataset available when no explicit dataset is specified, or may describe graphs availble for explicit inclusion in the dataset via protocol or query level features. (@@ fix wording as per AndyS's email)
The rdfs:domain of sd:datasetDescription is sd:Service.
Releates an instance of sd:Service to a URL from which a dataset description can be retrieved. If retrieved, the dataset description has the same meaning as if it had been referened directly with sd:datasetDescription.
The rdfs:domain of sd:datasetDescriptionURL is sd:Service.
The following HTTP trace illustrates the retrieval of a service description from the SPARQL service http://www.example/sparql/.
GET /sparql/ HTTP/1.1 Host: www.example
The SPARQL service responds with an RDF/XML encoded service description (no content negotiation or RDFa encoding is used):
HTTP/1.1 200 OK Date: Fri, 09 Oct 2009 17:31:12 GMT Server: Apache/1.3.29 (Unix) PHP/4.3.4 DAV/1.0.3 Connection: close Content-Type: application/rdf+xml <?xml version="1.0" encoding="utf-8"?> <rdf:RDF xmlns:ex="http://example/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:scovo="http://purl.org/NET/scovo#" xmlns:sd="http://www.w3.org/ns/sparql-service-description#" xmlns:void="http://rdfs.org/ns/void#"> <sd:Service> <sd:url rdf:resource="http://www.example/sparql/"/> <sd:extensionFunction> <sd:ScalarFunction rdf:about="java:com.ldodds.sparql.Distance"/> </sd:extensionFunction> <sd:datasetDescription> <rdf:Description> <ex:defaultGraph> <void:Dataset rdf:about="http://www.example/default-graph/"> <void:statItem> <rdf:Description> <scovo:dimension rdf:resource="http://rdfs.org/ns/void#numberOfTriples"/> <rdf:value rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">100</rdf:value> </rdf:Description> </void:statItem> </void:Dataset> </ex:defaultGraph> <ex:namedGraph> <void:Dataset rdf:about="http://www.example/named-graph/"> <void:statItem> <rdf:Description> <scovo:dimension rdf:resource="http://rdfs.org/ns/void#numberOfTriples"/> <rdf:value rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">2000</rdf:value> </rdf:Description> </void:statItem> </void:Dataset> </ex:namedGraph> </rdf:Description> </sd:datasetDescription> </sd:Service> </rdf:RDF>
This RDF describes a SPARQL service available at the URL http://www.example/sparql/ that supports the java:com.ldodds.sparql.Distance extension function, and has a dataset with a default graph and one named graph, both described using the voiD vocabulary. The default graph contains 100 triples while the graph named http://www.example/named-graph/ contains 2000 triples.
$Log: Overview.html,v $ Revision 1.5 2018/10/09 13:27:51 denis fix validation of xhtml documents Revision 1.4 2017/10/02 10:39:34 denis add fixup.js to old specs Revision 1.3 2009/10/23 14:16:41 ivan *** empty log message *** Revision 1.2 2009/10/22 07:20:57 ivan *** empty log message *** Revision 1.1 2009/10/21 14:25:02 ivan *** empty log message *** Revision 1.5 2009/10/21 03:29:49 lfeigenb pubrules fixes Revision 1.4 2009/10/21 03:20:50 lfeigenb fixed this version URI Revision 1.3 2009/10/21 03:19:15 lfeigenb publication prep Revision 1.2 2009/10/20 20:47:23 lfeigenb validation errors Revision 1.6 2009/10/20 19:45:51 lfeigenb small fixes for naming and cleanup Revision 1.5 2009/10/20 18:03:06 lfeigenb move to using the shared XML spec materials Revision 1.4 2009/10/20 15:53:20 lfeigenb updated NS URI as per Oct-20 meeting Revision 1.3 2009/10/20 14:25:47 gwilliam Fixed base.uri. Commented out TURTLE reference. Revision 1.2 2009/10/20 13:59:34 gwilliam Removed duplicate namespace section. Revision 1.1 2009/10/20 04:21:12 gwilliam CREATED