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SPARQL Service Description

An Introduction

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What is SPARQL?

•  RDF Query language based on RDQL •  Used to retrieve and manipulate data stored in RDF format •  Uses SQL-like syntax

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SPARQL Protocol and RDF Query Language

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Example SPARQL Query

“Return the full names of all people in the graph” PREFIX vCard: <http://www.w3.org/2001/vcard-rdf/3.0#> SELECT ?fullName WHERE {?x vCard:FN ?fullName} result: fullName ================= "John Smith" "Mary Smith"

@prefix ex: <http://example.org/#> . @prefix vcard: <http://www.w3.org/2001/vcard-rdf/3.0#> . ex:john vcard:FN "John Smith" ; vcard:N [ vcard:Given "John" ; vcard:Family "Smith" ] ; ex:hasAge 32 ; ex:marriedTo :mary . ex:mary vcard:FN "Mary Smith" ; vcard:N [ vcard:Given "Mary" ; vcard:Family "Smith" ] ; ex:hasAge 29 .

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What is a SPARQL Service Description?

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•  Method for discovering and •  Vocabulary for describing SPARQL Services •  Commonly referred to as a „SPARQL endpoint“ •  Provides mechanism by which informations can be discovered such as

–  Supported extension functions –  Details about the available dataset

•  Returns a service description when dereferenced using HTTP GET

SPARQL Service Description is ...

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SPARQL Service Description Properties

•  sd:endpoint –  a SPARQL endpoint

•  sd:feature –  a supported feature

•  sd:defaultEntailmentRegime –  entailment regime used for basic graph pattern matching

•  sd:extensionFunction –  a function that may be used in a SPARQL SELECT expression, or clauses like

FILTER, HAVING, GROUP BY, ...

•  sd:defaultDataset –  a description of the default dataset available when no explicit dataset is specified

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SPARQL Service Description Properties

•  sd:resultFormat –  a format for serializing query results

•  sd:defaultGraph –  relates an instance of sd:Dataset to the description of its default graph

•  sd:supportedLanguage –  relates an instance of sd:Service to a SPARQL language that it implements

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SPARQL Service Description Classes

•  sd:Service –  an instance of sd:Service represents a SPARQL service

•  sd:Feature •  sd:Language •  sd:EntailmentRegime •  sd:EntailmentProfile •  sd:GraphCollection •  sd:Dataset

–  represents an RDF dataset comprised of a default graph and zero or more named graphs

•  sd:Graph –  represents the desription of an RDF graph

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SPARQL Service Description Instances

•  sd:SPARQL10Query •  sd:SPARQL11Query •  sd:SPARQL11Update •  sd:DereferencedURIs •  sd:UnionDefaultGraph •  sd:RequiresDataset •  sd:EmptyGraphs •  sd:BasicFederatedQuery

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Example (Informative)

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!"#$%&"'("&"!"&")*"+',-.+'#)('%+"+'$/"'&"+%01)2'-34'5)'$/"'(#$#+"$'(%&5)2'6%"&7'"8#0%#19)'!%)*19)''%+"('5)':;<;=>'

"?@&"++59)'9&'"A2A'4.<>;-'*0#%+"''("!#%0$'2&#@/'B5$/'CDD'

$&5@0"+'

EF<G-34'")$#50H")$'&"25H"'

%+"('5)'I#+5*'2&#@/'@#J"&)'H#$*/5)2'

+%@@9&$"('@&9K0"'9!'$/"'")$#50H")$'&"25H"'

+"&85*"'")(@95)$'

'5H@0"H")$"(':LM-N<''

0#)2%#2"'

&"+%0$'+"&5#05O#19)'!9&H#$+'

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Thank you for your attention!