Question

我一直试图在rdflib图上运行查询（从schema.org加载schema.rdfa）来查找祖先。

E.g。根据{{3}}，祖先是 Thing＆gt; Organization＆gt; Corporation
这段代码完美无缺，给了我想要的输出，除了它不使用initBindings，我必须格式化查询字符串。

import rdflib
subject = rdflib.term.URIRef('http://schema.org/Corporation')
inplace_query = '''
SELECT ?class where {
    <%(subject_uri)s> rdfs:subClassOf* ?mid .
    ?mid rdfs:subClassOf* ?class .
}
group by ?class
order by count(?mid)
'''
iq = inplace_query % dict(subject_uri=subject.toPython())
print iq
# This prints out the following
'''
SELECT ?class where {
    <http://schema.org/Corporation> rdfs:subClassOf* ?mid .
    ?mid rdfs:subClassOf* ?class .
}
group by ?class
order by count(?mid)
'''

graph = rdflib.Graph()
graph.load("schema.rdfa", format="rdfa")
print list(graph.query(iq, initNs={"rdfs": "http://www.w3.org/2000/01/rdf-schema#"}))
# This prints out the following which is correct
'''
[
    (rdflib.term.URIRef(u'http://schema.org/Corporation'),),
    (rdflib.term.URIRef(u'http://schema.org/Organization'),),
    (rdflib.term.URIRef(u'http://schema.org/Thing'),)
]
'''

以下代码使用initBindings，但为我提供了额外的术语http://schema.org/Place。

import rdflib
from rdflib.plugins.sparql import prepareQuery
subject = rdflib.term.URIRef('http://schema.org/Corporation')
prepared_query_str = '''
SELECT ?class where {
    ?subject rdfs:subClassOf* ?mid .
    ?mid rdfs:subClassOf* ?class .
}
group by ?class
order by count(?mid)
'''
print prepared_query_str
# This prints the following output
'''
SELECT ?class where {
        ?subject rdfs:subClassOf* ?mid .
            ?mid rdfs:subClassOf* ?class .
}
group by ?class
order by count(?mid)
'''

graph = rdflib.Graph()
graph.load("schema.rdfa", format="rdfa")
print list(
    graph.query(
        prepared_query_str,
        initNs={"rdfs": "http://www.w3.org/2000/01/rdf-schema#"},
        initBindings={"subject": subject},
    )
)
# This prints out the following which is not correct ! Place does not belong here
'''
[
    (rdflib.term.URIRef(u'http://schema.org/Corporation'),),
    (rdflib.term.URIRef(u'http://schema.org/Place'),),
    (rdflib.term.URIRef(u'http://schema.org/Organization'),),
    (rdflib.term.URIRef(u'http://schema.org/Thing'),)
]
'''

当我将查询转换为准备好的查询时，我最初注意到了这个问题，并且不得不使用initBindings替换＆＃34; subject＆＃34;。我已将其缩小为initBindings问题，而不是prepareQuery问题，因此删除了准备好的查询编译。

这两个查询不应该产生完全相同的结果吗？

我已将Schema for Corporation视为可能的副本，但我使用的是initBindings，但仍然存在这种不一致的情况。

使用initBindings时rdflib SPARQL查询的不同输出

0 个答案: