Examples from the lectures

This page contains code examples from the lectures.

S02

Getting started with RDFlib

from inspect import formatargspec
from rdflib import Graph, Literal, RDF, FOAF, Namespace

g = Graph()

EX = Namespace('http://ex.org/')

g.add((EX.Bob, RDF.type, FOAF.Person))
g.add((EX.Alice, RDF.type, FOAF.Person))
g.add((EX.Carol, RDF.type, FOAF.Person))
g.add((EX.Bob, FOAF.knows, EX.Alice))
g.add((EX.Bob, FOAF.knows, EX.Carol))

g.add((EX.Bob, FOAF.name, Literal('Bob')))
g.add((EX.Alice, FOAF.name, Literal('Alice')))
g.add((EX.Carol, FOAF.name, Literal('Carol')))

g.namespace_manager.bind('ex', EX)

print(g.serialize(format='json-ld'))

for p, o in g[ EX.Bob : : ]:
    print(p, o)


g2 = Graph()
g2.parse('https://www.wikidata.org/entity/Q935079.ttl')
print(g2.serialize())

S03

Local query with RDFlib

from rdflib import Graph, Namespace

REX = Namespace('http://example.org/royal#')

g = Graph()
g.parse('family.ttl', format='ttl')
res = g.query("""
    CONSTRUCT {
        ?child fam:aunt ?aunt .
    } WHERE {
        ?child fam:hasParent / fam:hasSister ?aunt .
    }
""",
    initNs={
        'fam': 'http://example.org/family#'
    },
    initBindings={
        'child': REX.SverreMagnus
    })

S04

Remote query with SPARQLWrapper

import SPARQLWrapper

endpoint = 'http://sandbox.i2s.uib.no/bigdata/namespace/kb/sparql'

paper_uri = 'http://semanticscholar.org/paper/c93a37e6922e09f34fc093f7e4f9675775d4557d'

client = SPARQLWrapper.SPARQLWrapper(endpoint=endpoint)
client.setReturnFormat('json')
client.setQuery(f'''
    DESCRIBE <{paper_uri}>
''')
res = client.queryAndConvert()

Remote update with SPARQLWrapper

client.setReturnFormat('xml')
client.setMethod('POST')
client.setQuery('''
    DELETE DATA {
        <http://example.org/Abra> <http://example.org/ka> <http://example.org/Dabra> .
    }
''')
res = client.queryAndConvert()
client.setMethod('GET')

Local update with RDFlib

from rdflib import Graph, Namespace

g = Graph()
g.parse('family.ttl', format='turtle')

FAM = Namespace('http://example.org/family#')
g.update('''
    DELETE {
        ?child fam:hasAunt ?parent .
    } INSERT {
        ?child fam:hasAunt ?sister .
    } WHERE {
        ?child fam:hasParent ?parent .
        ?parent fam:hasSister ?sister .
    }
    ''',
    initNs={
        'fam': FAM
    })

print(g.serialize(format='turtle'))

S07

RDFS programming with owlrl .

Syllogism (rule rdfs9)

from rdflib import Graph, RDF, RDFS, OWL, Namespace
import owlrl

EX = Namespace('http://example.org#')

g = Graph()
g.bind('', EX)
NS = {
    '': EX,
    'rdf': RDF,
    'rdfs': RDFS,
}
g.update("""
INSERT DATA {
    :Socrates rdf:type :Man .
    :Man rdfs:subClassOf :Mortal .
}
""", initNs=NS)

rdfs_engine = owlrl.RDFSClosure.RDFS_Semantics(g, True, False, False)
rdfs_engine.closure()
rdfs_engine.flush_stored_triples()

res = g.query("""
ASK { :Socrates rdf:type :Mortal . }
""", initNs=NS)
print(res.askAnswer)

Domain and range (rules rdfs2-3)

from rdflib import Graph, RDF, RDFS, OWL, Namespace
import owlrl

EX = Namespace('http://example.org#')

g = Graph()
g.bind('', EX)
NS = {
    '': EX,
    'rdf': RDF,
    'rdfs': RDFS,
}
g.update("""
INSERT DATA {
    :Socrates :husbandOf :Xantippe .
    :husbandOf rdfs:domain :Man .
    :husbandOf rdfs:range :Woman .
}
""", initNs=NS)

rdfs_engine = owlrl.RDFSClosure.RDFS_Semantics(g, True, False, False)
rdfs_engine.closure()
rdfs_engine.flush_stored_triples()

res = g.query("""
ASK { :Xantippe rdf:type :Woman . }
""", initNs=NS)
print(res.askAnswer)

S08

owl:inverseOf

from rdflib import Graph, Namespace, RDF, RDFS, FOAF
import owlrl


EX = Namespace('http://ex.org/')

g = Graph()
g.bind('', EX)
g.add((EX.Andreas, RDF.type, EX.Teacher))
g.add((EX.Martin, RDF.type, EX.Teacher))
g.add((EX.Tobias, RDF.type, EX.Teacher))
g.add((EX.Martin, RDF.type, EX.Student))
g.add((EX.Tobias, RDF.type, EX.Student))
g.add((EX.Mariah, RDF.type, EX.Student))
g.add((EX.Bahareh, RDF.type, EX.Student))
# g.add((EX.Teacher, RDFS.subClassOf, FOAF.Person))
# g.add((EX.Student, RDFS.subClassOf, FOAF.Person))


g.update("""
INSERT DATA {
    :Martin :hasSupervisor :Andreas .
    :hasSupervisor owl:inverseOf :supervisorOf .
}
""")

This gives no response:

res = g.query("""
SELECT ?person WHERE {
    :Andreas :supervisorOf ?person .
}
""")
print(res.serialize(format='txt').decode())

Not this either:

engine = owlrl.CombinedClosure.RDFS_OWLRL_Semantics(g, False, False, False)
engine.closure()
engine.flush_stored_triples()

res = g.query("""
SELECT ?person WHERE {
    :Andreas :supervisorOf ?person .
}
""")
print(res.serialize(format='txt').decode())

But this prints out a response:

engine = owlrl.CombinedClosure.RDFS_OWLRL_Semantics(g, False, False, False)
engine.closure()
engine.flush_stored_triples()

res = g.query("""
SELECT ?person WHERE {
    :Andreas :supervisorOf ?person .
}
""")
print(res.serialize(format='txt').decode())

S11

Simple DL reasoning in Protege

Load the OWL file and use "Start reasoner" and "Synch reasoner" from the menues.