Construct and Python - Part 3 at Construct

This tutorial shows how to insert RDF from a file (joebloggs_foaf.rdf) into Construct. It then shows how to send a SPARQL query to query this data from Construct. The resulting QueryResults object is printed in N3 format.

from construct.proxy import proxy
from construct.constructservice import ServiceError
from rdflib.Graph import ConjunctiveGraph
# Create a new proxy object.
proxy = proxy()
print “Executing Script”
try:
# Generate a piece of FOAF RDF
store = ConjunctiveGraph()
store.load(“joebloggs_foaf.rdf”)
data = store.serialize(format=“nt”)
# Send the FOAF RDF to the data store
if(proxy.insert(data)):
# Now query for joebloggs web address
query = “”“SELECT ?nickname WHERE{
?subject <http://xmlns.com/foaf/0.1/name> “Joe Bloggs“.
?subject <http://xmlns.com/foaf/0.1/nick> ?nickname.}
““”
results = proxy.query(query)
print “Here is the N3 form of the QueryResults Object:”
print results
except ServiceError, e:
print e
# Close the proxy.
proxy.close()

If this script executes properly something like the following should be printed out:

Executing Script

Here is the N3 form of the QueryResults Object:

_:A6a94e801X3aX118515eda06X3aXX2dX7ffa <http://www.w3.org/2001/sw/DataAccess/tests/result-set#value> “joe” .

_:A6a94e801X3aX118515eda06X3aXX2dX7ffa <http://www.w3.org/2001/sw/DataAccess/tests/result-set#variable> “nickname” .

_:A6a94e801X3aX118515eda06X3aXX2dX7ffb <http://www.w3.org/2001/sw/DataAccess/tests/result-set#binding> _:A6a94e801X3aX118515eda06X3aXX2dX7ffa .

_:A6a94e801X3aX118515eda06X3aXX2dX7ffc <http://www.w3.org/2001/sw/DataAccess/tests/result-set#solution> _:A6a94e801X3aX118515eda06X3aXX2dX7ffb .

_:A6a94e801X3aX118515eda06X3aXX2dX7ffc <http://www.w3.org/2001/sw/DataAccess/tests/result-set#resultVariable> “nickname” .

_:A6a94e801X3aX118515eda06X3aXX2dX7ffc <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2001/sw/DataAccess/tests/result-set#ResultSet> .
This post is the final part of a python and Construct tutorial. Part 1 is here and part 2 is here.

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