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