def query_virtuoso(query=None,
graph=None,
output="ResultSet",
printQuery=False):
''' Function to query for data from the Virtuoso triplestore.
If only a specific graph should be searched, use the graph
variable to specify the graph-name.
If more then one graph should be used, it might be better to
directly name them in the query.
Returns a result set which is to be used like in this example:
resultset = query_virtuoso('SELECT DISTINCT * WHERE { ?s ?p "Juan" . }')
for resultRow in resultset:
print("%s has %s" % (resultRow["s"].value, resultRow["p"].value))
'''
if (query is None):
return None # no query, no result
if (graph is not None):
pos = query.lower().find('where')
query = query[0:pos] + " FROM <" + graph + "> " + query[pos:]
triplestore = Virtuoso("localhost", "dba", "dba", 8890, "/sparql")
result = triplestore.endpoint.query(query=query, output=output)
if (printQuery):
print query
return result
def delete_graph_virtuoso(graphIRI=None):
''' Method to delete the named graph graphIRI from the Virtuoso triplestore.
The default graph cannot be deleted with this function.
'''
triplestore = Virtuoso("localhost", "dba", "dba", 8890, "/sparql")
if graphIRI is None:
#nothing to do, return
return
triplestore.isql.clean_graph(url)
def virtuosotest():
""" Method for testing basic virtuoso connectivity
"""
triplestore = Virtuoso("localhost", "dba","dba", 8890, "/sparql")
results = triplestore.endpoint.query("SELECT * WHERE {?s ?p ?o} LIMIT 5")
graph = "http://my-graph"
ns = Namespace("http://my-name-space.com/#")
#Insert a triple into the triplestore
# <http://my-name-space.com/#user123> <http://my-name-space.com/#user123> "Juan"
triplestore.insert(graph, ns["user123"], ns["name"], Literal("Juan"))
#Deleting the triple just inserted
triplestore.delete(graph, ns["user123"], ns["name"], Literal("Juan"))
#Clean the whole graph (cant use triplestore.clean as there's a typo in the wrapper..)
triplestore.isql.clean_graph(graph)
def save_xmlrdf_to_virtuoso(xmlrdf=None, graphIRI=None):
''' Function to save data in XML/RDF format into the Virtuoso triplestore.
If the data should be saved in a named graph, provide a String for the
graph-name to graphIRI, otherwise data will be saved in the default graph
Returns 0 on failure, 1 on success
'''
if (xmlrdf is None):
#Nothing to add
return 0
triplestore = Virtuoso("localhost", "dba", "dba", 8890, "/sparql")
g = rdflib.Graph()
g.parse(data=xmlrdf, format="xml")
graph = graphIRI
for triple in g.triples((None, None, None)):
triplestore.insert(graph, triple[0], triple[1], triple[2])
return 1
def save_xmlrdf_to_virtuoso(xmlrdf=None,graphIRI=None):
''' Function to save data in XML/RDF format into the Virtuoso triplestore.
If the data should be saved in a named graph, provide a String for the
graph-name to graphIRI, otherwise data will be saved in the default graph
Returns 0 on failure, 1 on success
'''
if(xmlrdf is None):
#Nothing to add
return 0
triplestore = Virtuoso("localhost", "dba","dba", 8890, "/sparql")
g = rdflib.Graph()
g.parse(data=xmlrdf, format="xml")
graph = graphIRI
for triple in g.triples((None, None, None)):
triplestore.insert(graph,triple[0],triple[1],triple[2])
return 1
def virtuosotest():
""" Method for testing basic virtuoso connectivity
"""
triplestore = Virtuoso("localhost", "dba", "dba", 8890, "/sparql")
results = triplestore.endpoint.query("SELECT * WHERE {?s ?p ?o} LIMIT 5")
graph = "http://my-graph"
ns = Namespace("http://my-name-space.com/#")
#Insert a triple into the triplestore
# <http://my-name-space.com/#user123> <http://my-name-space.com/#user123> "Juan"
triplestore.insert(graph, ns["user123"], ns["name"], Literal("Juan"))
#Deleting the triple just inserted
triplestore.delete(graph, ns["user123"], ns["name"], Literal("Juan"))
#Clean the whole graph (cant use triplestore.clean as there's a typo in the wrapper..)
triplestore.isql.clean_graph(graph)
