[Wikidata-l] JSON-LD Provenance use case - Wikidata

13 Apr 2012


      I updated the JSON Talk page [1] with an example of using the JSON-LD named-graph syntax to express provenance information about some facts, based on a discussion of the use case in the W3C RDF Working Group [2] trying to express the following:
ParisFact1 expresses "Paris locatedIn France ."
ParisFact1 hasReference EncyclopediaBritannica, Wikipedia, Brockhaus.
ParisFact2 Paris hasPopulation 7000000^^int
ParisFact2 hasReference Wikipedia
The JSON-LD looks like the following:
{
   "@context": {
     "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
     "ex": "http://example.org/",
     "xsd": "http://www.w3.org/2001/XMLSchema#",
     "ex:locatedIn": {"@type": "@id"},
     "ex:hasPopulaton": {"@type": "xsd:integer"},
     "ex:hasReference": {"@type": "@id"}
   },
   "@graph": [
     {
       "@id": "http://example.org/ParisFact1",
       "@type": "rdf:Graph",
       "@graph": {
         "@id": "http://example.org/location/Paris#this",
         "ex:locatedIn": "http://example.org/location/France#this"
       },
       "ex:hasReference": ["http://www.britannica.com/", "http://www.wikipedia.org/", "http://www.brockhaus.de/"]
     },
     {
       "@id": "http://example.org/ParisFact2",
       "@type": "rdf:Graph",
       "@graph": {
         "@id": "http://example.org/location/Paris#this",
         "ex:hasPopulation": 7000000
       },
       "ex:hasReference": "http://www.wikipedia.org/"
     }
   ]
 }
Which could be expressed in TriG as:
@prefix ex: http://example.org/ .
 @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns# .
 @prefix xsd: http://www.w3.org/2001/XMLSchema# .
 {
   ex:ParisFact1 a rdf:Graph;
      ex:hasReference http://www.britannica.com/,
        http://www.wikipedia.org/,
        http://www.brockhaus.de/ .
   ex:ParisFact2 a rdf:Graph;
      ex:hasReference http://www.wikipedia.org/ .
 }
 ex:ParisFact1 {
   http://example.org/location/Paris#this ex:locatedIn http://example.org/location/France#this .
 }
 ex:ParisFact2 {
   http://example.org/location/Paris#this ex:hasPopulation 7000000 .
 }
Note that JSON-LD recently added support for named graphs [3].
Gregg
[1] http://meta.wikimedia.org/wiki/Talk:Wikidata/Data_model/JSON
[2] http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs-UC#.28C_priority.29_Wikidata
[3] http://json-ld.org/spec/latest/json-ld-syntax/#named-graphs
Gregg