Semantic Data Chapter 7 : The semantic web query ...Semantic Data Chapter 7 : The semantic web query...

Semantic Data

Chapter 7 : The semantic web query language

SPARQL

Jean-Louis Binot

1 18/03/2020Semantic Data

Sources

❑

❑

◼

◼

◼

❑

◼

◼

◼

2

Agenda

Querying RDF graphs1

SPARQL syntax and semantics2

Entailment regimes and OWL3

3

What is SPARQL ?

❑

◼

◼

❑

◼

◼

❑

◼

❑

SPARQL engine

SPARQL queries

SPARQL updatesRDF dataset

RDF store

4

Graph matching: basic idea

Dataset

Query pattern

Result

5

Graph matching: basic idea

❑

◼

◼

❑

◼

◼

◼

6

Graph matching: basic idea ./.

Dataset

Query pattern

Result

7

Graph matching: combining triples

DatasetQuery pattern

Result

8

Graph matching: traversing a graph

DatasetQuery pattern

Result

9

Agenda

Querying RDF graphs1

SPARQL syntax and semantics2

Entailment regimes and OWL3

10

A full example

SPARQL QUERY ENDPOINT

http://librdf.org/query/

DATASET FILE (Turtle)

RDF/XML

11

SPARQL basic query structure

❑

12

Graph patterns

❑

❑

◼

◼

◼

◼

◼

13

Examples

14

Matching literals and blank nodes

❑

❑

❑

◼

15

Query modifiers

❑

❑

❑

16

Query form DESCRIBE

❑

❑

17

Aggregates

❑

◼

◼

❑

18

Semantics of an answer to a graph pattern query

❑

◼

◼

❑

❑

◼

◼ ⊨

19

Agenda

Querying RDF graphs1

SPARQL syntax and semantics2

Entailment regimes and OWL3

20

Beyond RDF ?

❑

◼

◼

◼

❑

21

Reminder : RDF/RDFS entailment patterns

If S contains: then S RDF(S)_entails :

a p "v"^^d . a p _:b . _b rdf:type d .

a p b . p rdf:type rdf:Property .

any IRI a in D a rdf:type rdfs:Datatype .

p rdfs:domain x .

a p b .a rdf:type x .

p rdfs:range x .

a p b .b rdf:type x .

a p b . a rdf:type rdf:Resource .

a p b . b rdf:type rdf:Resource .

p rdfs:subPropertyOf q .

q rdfs:subPropertyOf r .p rdfs:subPropertyOf r .

a rdf:type rdf:Property . a rdfs:subPropertyOf a .

rdfs:subPropertyOf q .

a p b.a q b .

c rdf:type rdfs:Class . c rdfs:subClassOf rdf:Resource .

c rdfs:subClassOf d .

a rdf:type c.a rdf:type d .

c rdf:type rdfs:Class . c rdfs:subClassOf c .

c rdfs:subClassOf d .

d rdfs:subClassOf e .c rdfs:subClassOf e .

rdf:type rdfs:ContainerMembershipProperty . p rdfs:subPropertyOf rdfs:member .

d rdf:type rdfs:Datatype . d rdfs:subClassOf rdfs:Literal .

22

Influence of entailment regime

❑

❑

◼

◼

◼

◼

23

Querying OWL with SPARQL

❑

❑

❑

❑

24

Summary

❑

❑

❑

❑

❑

25

References

❑

26

THANK YOU

27