Cannot delete any triple from GraphDB using pythons SPARQLWrapper

Question

I am trying to delete a simple triple from GraphDB (version = GraphDB free) using python's SPARQLWrapper and the code snippet I found here: https://github.com/RDFLib/sparqlwrapper - Update example. I always get the following exception: SPARQLWrapper.SPARQLExceptions.QueryBadFormed: QueryBadFormed: a bad request has been sent to the endpoint, probably the sparql query is bad formed.

my code is:

    sparql = SPARQLWrapper('http://192.168.0.242:7200/repositories/DataCitation')
    sparql.setMethod(POST)

    sparql.setQuery("""
    PREFIX pub: <http://ontology.ontotext.com/taxonomy/>

    delete where {
        <http://ontology.ontotext.com/resource/tsk9hdnas934> pub:occupation "Cook".
    }
    """)

    results = sparql.query()
    print(results.response.read())

When I do an ask or select statement to the same endpoint I get a valid result. Only the update statements do not work.

this is the full stacktrace

/home/filip/anaconda3/envs/TripleStoreCitationFramework/bin/python /home/filip/PycharmProjects/TripleStoreCitationFramework/GraphDB/Playground.py
Traceback (most recent call last):
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/site-packages/SPARQLWrapper/Wrapper.py", line 1073, in _query
    response = urlopener(request)
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 531, in open
    response = meth(req, response)
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 640, in http_response
    response = self.parent.error(
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 569, in error
    return self._call_chain(*args)
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 502, in _call_chain
    result = func(*args)
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/urllib/request.py", line 649, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 400: 

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/filip/PycharmProjects/TripleStoreCitationFramework/GraphDB/Playground.py", line 6, in <module>
    citing.delete_triples("s")
  File "/home/filip/PycharmProjects/TripleStoreCitationFramework/GraphDB/DataCiting.py", line 32, in delete_triples
    results = sparql.query()
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/site-packages/SPARQLWrapper/Wrapper.py", line 1107, in query
    return QueryResult(self._query())
  File "/home/filip/anaconda3/envs/TripleStoreCitationFramework/lib/python3.8/site-packages/SPARQLWrapper/Wrapper.py", line 1077, in _query
    raise QueryBadFormed(e.read())
SPARQLWrapper.SPARQLExceptions.QueryBadFormed: QueryBadFormed: a bad request has been sent to the endpoint, probably the sparql query is bad formed.

Response: b'Missing parameter: query'

Does this answer your question? GraphDB Free 8.8 Sparql INSERT returning 400. INSERT not supported? — Jeen Broekstra
– Jeen Broekstra, Commented Aug 31, 2020 at 6:13

Sava Savov · Accepted Answer · 2020-08-31 05:48:07Z

4

The endpoint which you need to insert statements isn't the simple SPARQL endpoint you use for ordinary queries, but, rather, the dedicated /statements endpoint:

http:///repositories//statements

This endpoint is also used for DELETE statements.

You can look up some examples in the RDF4J documentation. Furthermore, if you are passing your data with a query string instead of it being a part of your request body, you need to be aware of the fact that it must start with a "?update=" instead of "?query=".opps

answered Aug 31, 2020 at 5:48

Sava Savov

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1 Comment

Vladimir Alexiev Over a year ago

In other words, the URL should be http://192.168.0.242:7200/repositories/DataCitation/statements?update=.... And if you use POST, you should use www-form-url-encoded with param update and value being the query

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