The Freebase RDF API allows applications to retrieve a subgraph of data connected to a specific Freebase object through a simple HTTP GET request. The URI for this request is simply the concatenation of the RDF service URL and the Freebase identifier (/type/object/id) with the slashes in the ID replaced with dots (this conversion to a “dot notation” makes the QNames with these identifiers much nicer.) So the the URI for the Topic about the movie Blade Runner (/en/blade_runner) becomes http://rdf.freebase.com/ns/en.blade_runner.
Mapping Freebase data to RDF
Every fact in Freebase gets mapped to a single RDF triple, except for the following exceptions.
1.The following triples are filtered out: •MID predicates
•Unnamed reversed predicates
•Any attribution predicates
2.All /type/object/key facts get duplicated in the following way: •Flattening the key with the namespace: (some-mid, “/type/object/key”, “/en/wikipedia/bob_dylan”)
•Using the namespace as the predicate: (some-mid, “/key/en/wikipedia”, “bob_dylan”)
3.The following facts are mapped to RDF schema to improve interoperability:
•/type/object/name → rdf:label
•/type/object/type → rdf:type
•/type/object/type → (rdfs:type rdfs:Class)
•owl:FunctionalProperty if /type/property/unique else
•rdfs:range ← /type/property/expected_type
•rdfs:domain ← /type/property/schema
•owl:inverseOf ← /type/property/reverse_property
The Freebase RDF API is a web service that will return all the known facts for a given topic including images and text blurbs. You can apply filters to the Topic API so that it only returns the property values that you’re interested. This is ideal for building topic pages and short summaries of an entity.