def is_subclass(self, qid_1, qid_2):
if qid_1 == qid_2:
return True
# Reply from cache if possible.
cache_key = self.cache_key(qid_1, qid_2)
if cache_key in self.cache:
return self.cache[cache_key]
# Prepare the query.
query = """
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
SELECT ( COUNT( 1 ) AS ?count ) WHERE {
wd:%s wdt:%s* wd:%s .
}
""" % (qid_1, self.subclass_pid, qid_2)
# Run the query.
results = sparql_wikidata(query)
# Cache the result.
retval = '1' == results['bindings'][0]['count']['value']
self.cache[cache_key] = retval
return retval
def build_cache(self, subclass_qid):
# Stop building the cache if we reached the needle.
if subclass_qid in self.cache.keys():
return
# Set the initial set.
self.cache[subclass_qid] = set()
# Prepare the query.
query = """
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
SELECT ?parent WHERE {
wd:%s wdt:%s ?parent .
}
""" % (subclass_qid, self.subclass_pid)
# Run the query.
results = sparql_wikidata(query)
for result in results["bindings"]:
q = to_q(result["parent"]["value"])
self.cache[subclass_qid].add(q)
def prefetch_children(self, qid, force=False):
"""
Prefetches (in Redis) all the children of a given class
"""
if qid in self.sets:
return # children are already prefetched
sparql_query = """
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
SELECT ?child WHERE { ?child wdt:%s* wd:%s
. FILTER( strstarts( str( ?child ), 'http://www.wikidata.org/entity/Q' ) )
}
""" % (self.subclass_pid, qid)
results = sparql_wikidata(sparql_query)
new_set = set()
for result in results["bindings"]:
child_qid = to_q(result["child"]["value"])
if child_qid: # this can fail if the entity is a property, lexeme…
new_set.add(int(child_qid[1:]))
self.sets[qid] = new_set
def __enter__(self):
self.query_results = sparql_wikidata(
self.query, endpoint=self.endpoint)['bindings']
return self