RDFLib

RDFLib is a pure Python package for working with RDF. RDFLib contains most things you need to work with RDF, including:
parsers and serializers for RDF/XML, N3, NTriples, N-Quads, Turtle, TriX, Trig and JSON-LD
a Graph interface which can be backed by any one of a number of Store implementations
store implementations for in-memory, persistent on disk (Berkeley DB) and remote SPARQL endpoints
a SPARQL 1.1 implementation - supporting SPARQL 1.1 Queries and Update statements
SPARQL function extension mechanisms

Graph databases are an excellent choice for applications based on network-like models. To standardize the syntax and semantics of such graphs, the W3C recommends Semantic Web Technologies, cp. Semantic Web.

SPARQL serves as a query language analogously to SQL or Cypher for these graphs. This notebook demonstrates the application of LLMs as a natural language interface to a graph database by generating SPARQL.

Disclaimer: To date, SPARQL query generation via LLMs is still a bit unstable. Be especially careful with UPDATE queries, which alter the graph.

Setting up

We have to install a python library:

!pip install rdflib

There are several sources you can run queries against, including files on the web, files you have available locally, SPARQL endpoints, e.g., Wikidata, and triple stores.

from langchain.chains import GraphSparqlQAChain
from langchain_community.graphs import RdfGraph
from langchain_openai import ChatOpenAI

API Reference:

graph = RdfGraph(
    source_file="http://www.w3.org/People/Berners-Lee/card",
    standard="rdf",
    local_copy="test.ttl",
)

Note that providing a local_file is necessary for storing changes locally if the source is read-only.

Refresh graph schema information

If the schema of the database changes, you can refresh the schema information needed to generate SPARQL queries.

graph.load_schema()

graph.get_schema

In the following, each IRI is followed by the local name and optionally its description in parentheses. 
The RDF graph supports the following node types:
<http://xmlns.com/foaf/0.1/PersonalProfileDocument> (PersonalProfileDocument, None), <http://www.w3.org/ns/auth/cert#RSAPublicKey> (RSAPublicKey, None), <http://www.w3.org/2000/10/swap/pim/contact#Male> (Male, None), <http://xmlns.com/foaf/0.1/Person> (Person, None), <http://www.w3.org/2006/vcard/ns#Work> (Work, None)
The RDF graph supports the following relationships:
<http://www.w3.org/2000/01/rdf-schema#seeAlso> (seeAlso, None), <http://purl.org/dc/elements/1.1/title> (title, None), <http://xmlns.com/foaf/0.1/mbox_sha1sum> (mbox_sha1sum, None), <http://xmlns.com/foaf/0.1/maker> (maker, None), <http://www.w3.org/ns/solid/terms#oidcIssuer> (oidcIssuer, None), <http://www.w3.org/2000/10/swap/pim/contact#publicHomePage> (publicHomePage, None), <http://xmlns.com/foaf/0.1/openid> (openid, None), <http://www.w3.org/ns/pim/space#storage> (storage, None), <http://xmlns.com/foaf/0.1/name> (name, None), <http://www.w3.org/2000/10/swap/pim/contact#country> (country, None), <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> (type, None), <http://www.w3.org/ns/solid/terms#profileHighlightColor> (profileHighlightColor, None), <http://www.w3.org/ns/pim/space#preferencesFile> (preferencesFile, None), <http://www.w3.org/2000/01/rdf-schema#label> (label, None), <http://www.w3.org/ns/auth/cert#modulus> (modulus, None), <http://www.w3.org/2000/10/swap/pim/contact#participant> (participant, None), <http://www.w3.org/2000/10/swap/pim/contact#street2> (street2, None), <http://www.w3.org/2006/vcard/ns#locality> (locality, None), <http://xmlns.com/foaf/0.1/nick> (nick, None), <http://xmlns.com/foaf/0.1/homepage> (homepage, None), <http://creativecommons.org/ns#license> (license, None), <http://xmlns.com/foaf/0.1/givenname> (givenname, None), <http://www.w3.org/2006/vcard/ns#street-address> (street-address, None), <http://www.w3.org/2006/vcard/ns#postal-code> (postal-code, None), <http://www.w3.org/2000/10/swap/pim/contact#street> (street, None), <http://www.w3.org/2003/01/geo/wgs84_pos#lat> (lat, None), <http://xmlns.com/foaf/0.1/primaryTopic> (primaryTopic, None), <http://www.w3.org/2006/vcard/ns#fn> (fn, None), <http://www.w3.org/2003/01/geo/wgs84_pos#location> (location, None), <http://usefulinc.com/ns/doap#developer> (developer, None), <http://www.w3.org/2000/10/swap/pim/contact#city> (city, None), <http://www.w3.org/2006/vcard/ns#region> (region, None), <http://xmlns.com/foaf/0.1/member> (member, None), <http://www.w3.org/2003/01/geo/wgs84_pos#long> (long, None), <http://www.w3.org/2000/10/swap/pim/contact#address> (address, None), <http://xmlns.com/foaf/0.1/family_name> (family_name, None), <http://xmlns.com/foaf/0.1/account> (account, None), <http://xmlns.com/foaf/0.1/workplaceHomepage> (workplaceHomepage, None), <http://purl.org/dc/terms/title> (title, None), <http://www.w3.org/ns/solid/terms#publicTypeIndex> (publicTypeIndex, None), <http://www.w3.org/2000/10/swap/pim/contact#office> (office, None), <http://www.w3.org/2000/10/swap/pim/contact#homePage> (homePage, None), <http://xmlns.com/foaf/0.1/mbox> (mbox, None), <http://www.w3.org/2000/10/swap/pim/contact#preferredURI> (preferredURI, None), <http://www.w3.org/ns/solid/terms#profileBackgroundColor> (profileBackgroundColor, None), <http://schema.org/owns> (owns, None), <http://xmlns.com/foaf/0.1/based_near> (based_near, None), <http://www.w3.org/2006/vcard/ns#hasAddress> (hasAddress, None), <http://xmlns.com/foaf/0.1/img> (img, None), <http://www.w3.org/2000/10/swap/pim/contact#assistant> (assistant, None), <http://xmlns.com/foaf/0.1/title> (title, None), <http://www.w3.org/ns/auth/cert#key> (key, None), <http://www.w3.org/ns/ldp#inbox> (inbox, None), <http://www.w3.org/ns/solid/terms#editableProfile> (editableProfile, None), <http://www.w3.org/2000/10/swap/pim/contact#postalCode> (postalCode, None), <http://xmlns.com/foaf/0.1/weblog> (weblog, None), <http://www.w3.org/ns/auth/cert#exponent> (exponent, None), <http://rdfs.org/sioc/ns#avatar> (avatar, None)

Querying the graph

Now, you can use the graph SPARQL QA chain to ask questions about the graph.

chain = GraphSparqlQAChain.from_llm(
    ChatOpenAI(temperature=0), graph=graph, verbose=True
)

chain.run("What is Tim Berners-Lee's work homepage?")

[1m> Entering new GraphSparqlQAChain chain...[0m
Identified intent:
[32;1m[1;3mSELECT[0m
Generated SPARQL:
[32;1m[1;3mPREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?homepage
WHERE {
    ?person foaf:name "Tim Berners-Lee" .
    ?person foaf:workplaceHomepage ?homepage .
}[0m
Full Context:
[32;1m[1;3m[][0m

[1m> Finished chain.[0m

"Tim Berners-Lee's work homepage is http://www.w3.org/People/Berners-Lee/."

Updating the graph

Analogously, you can update the graph, i.e., insert triples, using natural language.

chain.run(
    "Save that the person with the name 'Timothy Berners-Lee' has a work homepage at 'http://www.w3.org/foo/bar/'"
)

[1m> Entering new GraphSparqlQAChain chain...[0m
Identified intent:
[32;1m[1;3mUPDATE[0m
Generated SPARQL:
[32;1m[1;3mPREFIX foaf: <http://xmlns.com/foaf/0.1/>
INSERT {
    ?person foaf:workplaceHomepage <http://www.w3.org/foo/bar/> .
}
WHERE {
    ?person foaf:name "Timothy Berners-Lee" .
}[0m

[1m> Finished chain.[0m

'Successfully inserted triples into the graph.'

Let's verify the results:

query = (
    """PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n"""
    """SELECT ?hp\n"""
    """WHERE {\n"""
    """    ?person foaf:name "Timothy Berners-Lee" . \n"""
    """    ?person foaf:workplaceHomepage ?hp .\n"""
    """}"""
)
graph.query(query)

[(rdflib.term.URIRef('https://www.w3.org/'),),
 (rdflib.term.URIRef('http://www.w3.org/foo/bar/'),)]

Return SQARQL query

You can return the SPARQL query step from the Sparql QA Chain using the return_sparql_query parameter

chain = GraphSparqlQAChain.from_llm(
    ChatOpenAI(temperature=0), graph=graph, verbose=True, return_sparql_query=True
)

result = chain("What is Tim Berners-Lee's work homepage?")
print(f"SQARQL query: {result['sparql_query']}")
print(f"Final answer: {result['result']}")

[1m> Entering new GraphSparqlQAChain chain...[0m
Identified intent:
[32;1m[1;3mSELECT[0m
Generated SPARQL:
[32;1m[1;3mPREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?workHomepage
WHERE {
    ?person foaf:name "Tim Berners-Lee" .
    ?person foaf:workplaceHomepage ?workHomepage .
}[0m
Full Context:
[32;1m[1;3m[][0m

[1m> Finished chain.[0m
SQARQL query: PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?workHomepage
WHERE {
    ?person foaf:name "Tim Berners-Lee" .
    ?person foaf:workplaceHomepage ?workHomepage .
}
Final answer: Tim Berners-Lee's work homepage is http://www.w3.org/People/Berners-Lee/.

print(result["sparql_query"])

PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?workHomepage
WHERE {
    ?person foaf:name "Tim Berners-Lee" .
    ?person foaf:workplaceHomepage ?workHomepage .
}

RDFLib

Setting up​

API Reference:

Refresh graph schema information​

Querying the graph​

Updating the graph​

Return SQARQL query​

Help us out by providing feedback on this documentation page:

Setting up

Refresh graph schema information

Querying the graph

Updating the graph

Return SQARQL query