/sparql#
Corese implements SPARQL 1.1 Protocol. This endpoint allows you to query and update an RDF Dataset using SPARQL. The supported query forms are SELECT, ASK, CONSTRUCT, DESCRIBE or update (DELETE/INSERT).
The return data format can be specified in the Accept HTTP header and depends on the query form. The default return format is XML.
URL: {base URL}/sparql
SELECT or ASK#
The most often used SPARQL query form is SELECT for selecting or finding data. It returns the results in a tabular form that can be represented in many different formats.
ASK query form is used to determine whether a particular triple pattern exists in the specified data set. ASK returns true or false, depending on whether the solution or match exists. The result format can be modified depending on the client application.
Method: GET or POST
Headers:
- Content-Type:
application/x-www-form-urlencoded
application/sparql-query
- Accept:
application/sparql-results+json
application/sparql-results+xml
text/csv
text/tab-separated-values
text/plain
text/html
Parameters:
query: Required query string.
default-graph-uri: Optional list of default graph URIs. Default: none.
named-graph-uri: Optional list of named graph URIs. Default: none.
Note
The RDF Dataset for a query can be passed in the HTTP request as default-graph-uri and named-graph-uri parameters or in the SPARQL query string using the FROM and FROM NAMED keywords. If they differ the request parameters take precedence.
The default-graph-uri and named-graph-uri Have to be passed as query string parameters if using Content-Type: application/sparql-query header.
There are three ways to send a SPARQL query to a Corese endpoint:
- Send a query as a URL-encoded query string in the query parameter
The query string must be passed in the URL as query=….
- Send a query as a URL-encoded POST request.
The Content-Type header must be set to application/x-www-form-urlencoded. The query string must be passed in the POST request body as query=…
- Send a query directly in the POST request body.
The Content-Type header must be set to application/sparql-query. The query string must be passed in the POST request body.
All other parameters can be passed in the URL as query string parameters.
SELECT Request Example:
This example demonstrates three way to run the same query on the remote SPARQL endpoint https://corese.inria.fr/sparql.
The query is to find all the children who have a mother in the Humans dataset .
# GET /sparql?query=PREFIX%20%20humans%3A%20%3Chttp%3A%2F%2Fwww.inria.fr%2F2015%2Fhumans%23%3E%20%20SELECT%20%2A%20WHERE%20%7B%20%3Fchild%20humans%3AhasMother%20%3Fmother.%20%7D HTTP/1.1
# Host: https://corese.inria.fr
# Accept: application/sparql-results+json
QUERY='PREFIX humans: <http://www.inria.fr/2015/humans#>
SELECT * WHERE { ?child humans:hasMother ?mother. }'
curl -G \
--url https://corese.inria.fr/sparql \
--header "Accept: application/sparql-results+json" \
--data-urlencode "query=$QUERY"
# POST /sparql HTTP/1.1
# Host: https://corese.inria.fr
# Content-Type: application/sparql-query
# Accept: application/sparql-results+xml
# PREFIX humans: <http://www.inria.fr/2015/humans#>
# SELECT * WHERE { ?child humans:hasMother ?mother. }
QUERY='PREFIX humans: <http://www.inria.fr/2015/humans#>
SELECT * WHERE { ?child humans:hasMother ?mother. }'
curl -X POST \
--url https://corese.inria.fr/sparql \
--header "Content-Type: application/sparql-query" \
--header "Accept: application/sparql-results+json" \
--data "$QUERY"
{
"head": {
"vars": [ "child", "mother"]
},
"results": {
"bindings": [
{
"child": { "type": "uri", "value": "http://www.inria.fr/2015/humans-instances#Lucas"},
"mother": { "type": "uri", "value": "http://www.inria.fr/2015/humans-instances#Catherine"}
},
{
"child": { "type": "uri", "value": "http://www.inria.fr/2015/humans-instances#Catherine"},
"mother": { "type": "uri", "value": "http://www.inria.fr/2015/humans-instances#Laura"}
}
]
}
}
ASK Request Example:
# GET /sparql?query=PREFIX%20%20humans%3A%20%3Chttp%3A%2F%2Fwww.inria.fr%2F2015%2Fhumans%23%3E%20%20ASK%20%7B%20%3Fchild%20humans%3AhasMother%20%3Fmother.%20%7D' HTTP/1.1
# Host: https://corese.inria.fr
# Accept: application/sparql-results+json
ASK='PREFIX humans: <http://www.inria.fr/2015/humans#>
ASK { ?child humans:hasMother ?mother. }'
curl -G \
--url https://corese.inria.fr/sparql \
--header "Accept: application/sparql-results+json" \
--data-urlencode "query=$ASK"
{
"head": { } ,
"boolean" : true
}
CONSTRUCT or DESCRIBE#
CONSTRUCT query form is used to create new data from your existing data. DESCRIBE query form is used to retrieve all the triples associated with a resource. Both return results in RDF format.
Method: GET or POST
Headers:
- Content-Type:
application/x-www-form-urlencoded
application/sparql-query
- Accept:
application/ld+json
application/rdf+xml
application/turtle
application/trig
application/n-triples
application/n-quads
text/nt
There are also three ways to send these types of queries as described in the SELECT or ASK section.
CONSTRUCT Request Example:
# POST /sparql HTTP/1.1
# Content-Type: application/x-www-form-urlencoded
# Accept: application/turtle
# Host: https://corese.inria.fr
# query="PREFIX humans: <http://www.inria.fr/2015/humans#> CONSTRUCT { ?mother humans:hasChild ?child. } WHERE { ?child humans:hasMother ?mother. }"
QUERY='PREFIX humans: <http://www.inria.fr/2015/humans#>
CONSTRUCT { ?mother humans:hasChild ?child. }
WHERE { ?child humans:hasMother ?mother. }'
curl -X POST \
--url https://corese.inria.fr/sparql \
--header "Accept: application/turtle" \
--header "Content-Type: application/x-www-form-urlencoded" \
--data "query=$QUERY"
#POST /sparql HTTP/1.1
#Content-Type: application/sparql-query
#Accept: application/turtle
#Host: https://corese.inria.fr
#PREFIX humans: <http://www.inria.fr/2015/humans#>
#CONSTRUCT { ?mother humans:hasChild ?child. }
#WHERE { ?child humans:hasMother ?mother. }
QUERY='PREFIX humans: <http://www.inria.fr/2015/humans#>
CONSTRUCT { ?mother humans:hasChild ?child. }
WHERE { ?child humans:hasMother ?mother. }'
curl -X POST \
--url https://corese.inria.fr/sparql \
--header "Accept: application/turtle" \
--header "Content-Type: application/sparql-query" \
--data "$QUERY"
@prefix ns1: <http://www.inria.fr/2015/humans-instances#> .
@prefix humans: <http://www.inria.fr/2015/humans#> .
ns1:Catherine humans:hasChild ns1:Lucas .
ns1:Laura humans:hasChild ns1:Catherine .
DESCRIBE Request Example:
# GET /sparql?query="PREFIX%20%20humans%3A%20%3Chttp%3A%2F%2Fwww.inria.fr%2F2015%2Fhumans%23%3E%20%20DESCRIBE%20%3Chttp%3A%2F%2Fwww.inria.fr%2F2015%2Fhumans-instances%23Catherine%3E" HTTP/1.1
# Accept: text/nt
# Host: https://corese.inria.fr
QUERY='PREFIX humans: <http://www.inria.fr/2015/humans#>
DESCRIBE <http://www.inria.fr/2015/humans-instances#Catherine>'
curl -G \
--url https://corese.inria.fr/sparql \
--header "Accept: application/turtle" \
--data-urlencode "query=$QUERY"
@prefix ns1: <http://www.inria.fr/2015/humans-instances#> .
@prefix humans: <http://www.inria.fr/2015/humans#> .
ns1:Lucas humans:hasMother ns1:Catherine .
ns1:Karl humans:hasSpouse ns1:Catherine .
ns1:Catherine humans:hasMother ns1:Laura ;
humans:name "Catherine"@fr ;
a humans:Woman .
Update (DELETE/INSERT)#
This operation allows to update the RDF dataset. The supported update operations are INSERT DATA, DELETE DATA, DELETE WHERE, INSERT WHERE.
Method: POST
Headers:
- Content-Type:
application/x-www-form-urlencoded
application/sparql-update
- Accept:
application/sparql-results+json
application/sparql-results+xml
application/turtle
text/plain
Parameters:
update: Required parameter for the update operation.
using-graph-uri: Optional list of graph URIs for the update operation. Default: none.
using-named-graph-uri: Optional list of named graph URIs for the update operation. Default: none.
access: Optional access key that may give access to the protected features on the remote servers. Default: none.
Note
Use of the using-graph-uri and using-named-graph-uri parameters together with the USING, USING NAMED, or WITH clauses in the query is not permitted.
Note
SPARQL Update operations may not be authorized by a remote server. To execute an update operation on a remote server, the access parameter must be set to the access key that gives access to the protected features on the remote server.
There are two ways to send the update query to a Corese endpoint:
- Send an update query as a URL-encoded POST request.
The Content-Type header must be set to application/x-www-form-urlencoded. The update string must be passed in the POST request body as update=…. as well as and the *-graph-uri parameters.
- Send an update query directly in the POST request body.
The Content-Type header must be set to application/sparql-query. The update string must be passed in the POST request body.
Note
The ‘using-graph-uri’ and ‘using-named-graph-uri’ parameters have to be passed as query string parameters in the POST direct.
INSERT Request Example:
To execute this example we recommend launching the Corese Docker container.
# POST /sparql
# Host: https://localhost:8080
# Content-Type: `application/x-www-form-urlencoded`
# update='PREFIX dc: <http://purl.org/dc/elements/1.1/> INSERT DATA { <http://example/book1> dc:title "A new book" .}'
QUERY='PREFIX dc: <http://purl.org/dc/elements/1.1/>
INSERT DATA { <http://example/book1> dc:title "A newer book" . }'
GRAPH='http://example.org/graph'
curl -X POST \
--url http://localhost:8080/sparql \
--header "Content-Type: application/x-www-form-urlencoded" \
--data "update=$QUERY" \
--data "using-graph-uri=$GRAPH"
# POST /sparql
# Host: https://localhost:8080
# Content-Type: application/sparql-update
#
# PREFIX dc: <http://purl.org/dc/elements/1.1/>
# INSERT DATA { <http://example/book1> dc:title "A new book" .}
QUERY='PREFIX dc: <http://purl.org/dc/elements/1.1/>
INSERT DATA { <http://example/book1> dc:title "A newer book" . }'
GRAPH='http://example.org/graph'
curl -X POST \
--url http://localhost:8080/sparql?using-graph-uri="$GRAPH" \
--header "Content-Type: application/sparql-update" \
--data "$QUERY" -v
<?xml version="1.0" ?>
<sparql
xmlns='http://www.w3.org/2005/sparql-results#'>
<head></head>
<results>
<result></result>
</results>
</sparql>
HTTP/1.1 200 OK
Date: Tue, 25 Jun 2024 14:54:47 GMT
Access-Control-Allow-Origin: *
Content-Type: text/plain
Content-Length: 0
Server: Jetty(11.0.14)
Note
The update query returns an empty result set formatted according to the Accept header if the Content-Type:application/x-www-form-urlencoded and if the update operation is successful.
The update query returns no body and Length=0 if the Content-Type:application/sparql-update and if the update operation is successful.
If the update operation fails, the response status code is 500 and the response body contains an error message.