DBpedia

DBpedia (from "DB" for "database") is a project aiming to extract structured content from the information created in the Wikipedia project. This structured information is made available on the World Wide Web. DBpedia allows users to semantically query relationships and properties of Wikipedia resources, including links to other related datasets.

In 2008, Tim Berners-Lee described DBpedia as one of the most famous parts of the decentralized Linked Data effort.

Background

The project was started by people at the Free University of Berlin and Leipzig University''DBpedia: A Nucleus for a Web of Open Data'', available a

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/ref> in collaboration with OpenLink Software, and is now maintained by people at the University of Mannheim and Leipzig University. The first publicly available dataset was published in 2007. The data is made available under free licences (CC-BY-SA), allowing others to reuse the dataset; it doesn't however use an open data license to waive the sui generis database rights.

Wikipedia articles consist mostly of free text, but also include structured information embedded in the articles, such as "infobox" tables (the pull-out panels that appear in the top right of the default view of many Wikipedia articles, or at the start of the mobile versions), categorization information, images, geo-coordinates and links to external Web pages. This structured information is extracted and put in a uniform dataset which can be queried.

Dataset

The 2016-04 release of the DBpedia data set describes 6.0 million entities, out of which 5.2 million are classified in a consistent ontology, including 1.5 million persons, 810,000 places, 135,000 music albums, 106,000 films, 20,000 video games, 275,000 organizations, 301,000 species and 5,000 diseases. DBpedia uses the Resource Description Framework (RDF) to represent extracted information and consists of 9.5 billion RDF triples, of which 1.3 billion were extracted from the English edition of Wikipedia and 5.0 billion from other language editions.

From this data set, information spread across multiple pages can be extracted. For example, book authorship can be put together from pages about the work, or the author.

One of the challenges in extracting information from Wikipedia is that the same concepts can be expressed using different parameters in infobox and other templates, such as and . Because of this, queries about where people were born would have to search for both of these properties in order to get more complete results. As a result, the DBpedia Mapping Language has been developed to help in mapping these properties to an ontology while reducing the number of synonyms. Due to the large diversity of infoboxes and properties in use on Wikipedia, the process of developing and improving these mappings has been opened to public contributions.

Version 2014 was released in September 2014. A main change since previous versions was the way abstract texts were extracted. Specifically, running a local mirror of Wikipedia and retrieving rendered abstracts from it made extracted texts considerably cleaner. Also, a new data set extracted from Wikimedia Commons was introduced.

As of June 2021, DBPedia contains over a 850 million triples.

Examples

DBpedia extracts factual information from Wikipedia pages, allowing users to find answers to questions where the information is spread across multiple Wikipedia articles. Data is accessed using an SQL-like query language for RDF called SPARQL.

For example, if one were interested in the Japanese ''shōjo'' manga series ''Tokyo Mew Mew'', and wanted to find the genres of other works written by its illustrator Mia Ikumi.

DBpedia combines information from Wikipedia's entries on ''Tokyo Mew Mew'', Mia Ikumi and on works such as ''Super Doll Licca-chan'' and ''Koi Cupid''. Since DBpedia normalises information into a single database, the followin
query
can be asked without needing to know exactly which entry carries each fragment of information, and will list related genres:

PREFIX dbprop:
PREFIX db:
SELECT ?who, ?WORK, ?genre WHERE

Use cases

DBpedia has a broad scope of entities covering different areas of human knowledge. This makes it a natural hub for connecting datasets, where external datasets could link to its concepts. The DBpedia dataset is interlinked on the RDF level with various other Open Data datasets on the Web. This enables applications to enrich DBpedia data with data from these datasets. , there are more than 45 million interlinks between DBpedia and external datasets including: Freebase, OpenCyc, UMBEL, GeoNames, MusicBrainz, CIA World Fact Book, DBLP, Project Gutenberg, DBtune Jamendo, Eurostat, UniProt, Bio2RDF, and US Census data. The Thomson Reuters initiative OpenCalais, the Linked Open Data project of ''The New York Times'', the Zemanta API and DBpedia Spotlight also include links to DBpedia. The BBC
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