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Re: json-ld and sparql

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Tue, 15 Mar 2016 12:19:35 -0400
To: public-linked-json@w3.org
Message-ID: <56E83617.9050801@openlinksw.com>
On 3/15/16 11:53 AM, John Walker wrote:
> Hi Jean-Claude,
>
> Try using the CONSTRUCT form of SPARQL and use Accept header to
> request results in JSON-LD.
>
> prefix schema: <http://schema.org/>
> construct where {
> ?p a schema:Place .
> ?p rdfs:label ?name .
> ?p geo:lat ?lat .
> ?p geo:long ?lon .
> }
> LIMIT 5
>
> Regards,
> John

Hi John,

As per my earlier comment, the following will do:

prefix schema: <http://schema.org/>
*describe ?p* where {
?p a schema:Place .
?p rdfs:label ?name .
?p geo:lat ?lat .
?p geo:long ?lon .
}
LIMIT 5

and the JSON-LD set as the output format.

SPARQL Query Editor Source Code Link:


curl -i
"http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&qtxt=prefix+schema%3A+%3Chttp%3A%2F%2Fschema.org%2F%3E%0D%0Adescribe++%3Fp++where+%7B%0D%0A%3Fp+a+schema%3APlace+.%0D%0A%3Fp+rdfs%3Alabel+%3Fname+.%0D%0A%3Fp+geo%3Alat+%3Flat+.%0D%0A%3Fp+geo%3Along+%3Flon+.%0D%0A%7D+LIMIT+5&format=application%2Fld%2Bjson&CXML_redir_for_subjs=121&CXML_redir_for_hrefs=&timeout=30000&debug=on"


Kingsley
>
> On 15 Mar 2016, at 14:35, "Jean-Claude Moissinac"
> <jean-claude.moissinac@telecom-paristech.fr
> <mailto:jean-claude.moissinac@telecom-paristech.fr>> wrote:
>
>> I'm trying to find best practices in the use of a json output from a
>> sparql endpoint
>> For exemple the request on dbpedia :
>> prefix schema: <http://schema.org/>
>> select distinct ?p ?name ?lat ?lon where {
>> ?p a schema:Place .
>> ?p rdfs:label ?name .
>> ?p geo:lat ?lat .
>> ?p geo:long ?lon .
>> } LIMIT 5
>> give me as json output
>> { "head": { "link": [], "vars": ["p", "name", "lat", "lon"] },
>>   "results": { "distinct": false, "ordered": true, "bindings": [
>>     { "p": { "type": "uri", "value": "http://dbpedia.org/resource/Cameron_Parish,_Louisiana" }	, "name": { "type": "literal", "xml:lang": "en", "value": "Cameron Parish, Louisiana" }	, "lat": { "type": "typed-literal", "datatype": "http://www.w3.org/2001/XMLSchema#float", "value": "29.85" }	, "lon": { "type": "typed-literal", "datatype": "http://www.w3.org/2001/XMLSchema#float", "value": "-93.2" }},
>>     { "p": { "type": "uri", "value": "http://dbpedia.org/resource/Cameron_Parish,_Louisiana" }	, "name": { "type": "literal", "xml:lang": "ar", "value": "\u0645\u0642\u0627\u0637\u0639\u0629 \u0643\u0627\u0645\u064A\u0631\u0648\u0646 (\u0644\u0648\u064A\u0632\u064A\u0627\u0646\u0627)" }	, "lat": { "type": "typed-literal", "datatype": "http://www.w3.org/2001/XMLSchema#float", "value": "29.85" }	, "lon": { "type": "typed-literal", "datatype": "http://www.w3.org/2001/XMLSchema#float", "value": "-93.2" }},
>> ... < cut for clarity >
>>  }} ] } }
>> We loose the fact that ?p is a Place. We can factorize the 'type' on
>> the table of results. And finally get a table of objects like thos one
>> {
>>     "p ":  "http://dbpedia.org/resource/Cameron_Parish,_Louisiana",
>> "name": "Cameron Parish, Louisiana",
>> "pos": { "lat": 29.85, "long": 93.2 }
>> }
>> I suppose some results can be obtained by using a context and some
>> others by framing.
>> Can we point me on ideas for clarification?
>> Many thanks in advance
>> --
>> Jean-Claude Moissinac
>>
>>
>> Cet e-mail a été envoyé depuis un ordinateur protégé par Avast.
>> www.avast.com
>> <https://www.avast.com/fr-fr/lp-safe-emailing?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=OA-2109-A>
>>
>>


-- 
Regards,

Kingsley Idehen	      
Founder & CEO 
OpenLink Software     
Company Web: http://www.openlinksw.com
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Received on Tuesday, 15 March 2016 16:19:59 UTC

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