Knowledge Representation VII - IKT507. SPARQL stands for SPARQL Protocol And RDF Query Language

Transcription

1 Knowledge Representation VII - IKT507 This sentence is false! PARQL stands for PARQL Protocol And RDF Query Language Jan Pettersen Nytun, UiA 1

2 The emantic Web tack Hierarchy of languages, where each layer exploits and uses capabilities of the layers below. / XML chema Jan Pettersen Nytun, UiA, page 2

3 [4]: RDF provides a simple way to represent distributed data. The triple is the simplest way to represent a named connection between two things...the standard way to access RDF data uses a query language called PARQL PARQL query patterns are represented in a variant of Turtle. Jan Pettersen Nytun, UiA, page 3

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8 A imple Query [3] Find the title of a book from the given data graph RDF data: < < "PARQL Tutorial".. Typically it contains a set of triple patterns called a basic graph pattern, where subject, predicate and object may be a variable. PARQL query: ELECT?title WHERE { Variable basic graph pattern < < } A basic graph pattern matches a subgraph of the RDF data when RDF terms from that subgraph may be substituted for the variables. Query result: title "PARQL Tutorial" Jan Pettersen Nytun, UiA, page 8

9 Multiple Matches [3] The following two subsets of the data provided the two matches:

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12 Given ntology - : < < rdf:type owl:ntology. :hason rdf:type owl:bjectproperty. :Female rdf:type owl:class ; rdfs:subclassf :Human. :Human rdf:type owl:class. :Male rdf:type owl:class ; rdfs:subclassf :Human. :HaraldVofNorway rdf:type owl:namedindividual ; rdfs:label "Harald V". Jan Pettersen Nytun, UiA,, page 12

13 electing All Triples Jan Pettersen Nytun, UiA, ntologies, page 13

14 PREFIX rdf: < PREFIX owl: < PREFIX rdfs: < PREFIX xsd: < ELECT DITINCT?subject?predicate?object WHERE {?subject?predicate?object. } RDER BY?subject Jan Pettersen Nytun, UiA, ntologies, page 14

15 CNTRUCT tatement PREFIX : < PREFIX rdf: < PREFIX owl: < PREFIX rdfs: < PREFIX xsd: < construct {?son :hasparent?father} WHERE {?father :hason?son. } Jan Pettersen Nytun, UiA, page 15

16 rdfs:subclassf The members of one class (the subclass) are also members of the other (the super class). :Female rdf:type owl:class ; rdfs:subclassf :Human. Tools like reasoners understands the semantics of subclassf. It can also be described with PARQL: construct {?resourse rdf:type?theuperclass} WHERE {?theubclass rdfs:subclassf?theuperclass.?resourse rdf:type?theubclass } Jan Pettersen Nytun, UiA, 16

17 rdfs:subproperty f The pair related by one property (the sub property) are included in the other (the super property). :hason rdf:type owl:bjectproperty ; rdfs:subpropertyf :isparentto. It can also be described with PARQL: Jan Pettersen Nytun, UiA, 17

18 rdfs:subproperty f The pair related by one property (the sub property) are included in the other (the super property). :hason rdf:type owl:bjectproperty ; rdfs:subpropertyf :isparentto. It can also be described with PARQL: construct {? subject?theuperproperty? object } WHERE {?theubproperty rdfs:subpropertyf?theuperproperty.?subject?theubproperty?object } Jan Pettersen Nytun, UiA, 18

19 References [1] Book: David Poole and Alan Mackworth, Artificial Intelligence: Foundations of Computational Agents, Cambridge University Press, 2010, [2] [3] PARQL Query Language for RDF, W3C Recommendation 15 January [4] emantic Web for the Working ntologist, econd Edition: Effective Modeling in RDF and WL, May 20, 2011, by Dean Allemang, James Hendler Jan Pettersen Nytun, UIA, page 19