DBPedia

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Freebase and DBpedia are very similar projects; as they both extract structured data from Wikipedia and make it available as RDF. There are however a number of major differences from the range of data sources, the ability to edit content, and the structure of the organizations. Both are part of the Web of data and there are many connections between topics in Freebase and in DBpedia, and interactions between the communities.

Contents

Overview

Freebase and DBpedia have different schemas, different identifiers, and different goals. Through the common link of Wikipedia it has been possible to link some Freebase topics to DBpedia resources. This can be seen in Freebase's RDF output where a number of OWL:SameAs RDF identifiers point to DBpedia.

The DBpedia ontology has been manually created based on the most commonly used infoboxes within Wikipedia. The ontology currently covers over 170 classes which form a subsumption hierarchy and have 940 properties. The ontology is instantiated by a new infobox data extraction method which is based on hand-generated mappings of Wikipedia infoboxes to the DBpedia ontology.

Differences between the two projects include:

  • Freebase imports data from a wide variety of sources, not just Wikipedia, whereas DBpedia focuses on just Wikipedia data
  • DBpedia is funded by grants/sponsorships from various organisations, while Freebase is run by Google, an incorporated company.
  • Freebase is user-editable and contributions can be made through a public interface, whereas DBpedia requires that you edit Wikipedia for the change to appear in DBpedia

Similarities include:

DBpedia stores its data as RDF triples in a 3rd-party triple store.
Freebase stores its data as n-tuples in a proprietary tuple store.

Both communities make their data available as RDF.

Freebase provides complete data dumps.
DBpedia provides complete data dumps

DBpedia schema mappings can be edited by the community.
Freebase schema & data can be edited by the community.

DBpedia data is automatically generated from Wikipedia several times a year.
Wikipedia data is automatically imported into Freebase after two weeks.

DBpedia lets you query its data via a SPARQL endpoint.
Freebase lets you query its data via an MQL API.

DBpedia has strong connections to the Semantic Web research community.
Freebase has strong connections to the open data / startup community.

DBpedia tools are predominantly developed by 3rd parties and the open-source community.
Freebase tools are predominantly developed by Google and the Freebase community.

Instance links

3.6 million Freebase topics and DBpedia 3.8 resources were linked as of June 2012, up from the 2.4 million links when they were first linked in November 15, 2008. This linkage is mechanically generated and 100% accurate, because both databases link to Wikipedia. In RDF, they are connected with owl:sameAs predicates.

An example of DBpedia linking to Freebase: http://dbpedia.org/page/Tetris Freebase linking back: http://rdf.freebase.com/rdf/en.tetris

The entire set of links can also be downloaded as a single file (45 MB).

Ontology comparisons

People have also done work mapping between the two ontologies.

Type correlations

Here is the Freebase and DBpedia type correlations by Kingsley Idehen:

Link oriented Dataset (linkset) Graph IRI: <http://dbpedia.org/linkset/yago_freebase_type_correlation#>

Sample SPARQL:

SELECT DISTINCT *
FROM <http://dbpedia.org/linkset/yago_freebase_type_correlation#>
WHERE {?s ?p ?o}
LIMIT 50

Above via SPARQL Query over SPARQL Protocol URL: http://pnt.me/OnMzkM

Sample Links via Faceted Browser Interface (http://dbpedia.org/fct):

1. [1] 2. [2] -- Freebase Person Types Correlation 3. [3] -- Usage Stats re. Freebase Person Types Correlation

Property Correllations

Incomplete task. discussion

here

See also

Personal tools