Last updated
Main page of Wikidata
Type of site
Available inmultiple languages, Wikidatan
Owner Wikimedia Foundation, Inc. [1] [2]
Created byWikidata editors
Alexa rankDecrease Positive.svg 9,195 (February 2019) [3]
Launched29 October 2012;6 years ago (2012-10-29) [4]

Wikidata is a collaboratively edited knowledge base hosted by the Wikimedia Foundation. It is a common source of open data that Wikimedia projects such as Wikipedia can use, [5] [6] and anyone else, under a public domain license. This is similar to the way Wikimedia Commons provides storage for media files and access to those files for all Wikimedia projects, and which are also freely available for reuse. Wikidata is powered by the software Wikibase. [7]

Wiki type of website that visitors can edit

A wiki is a knowledge base website on which users collaboratively modify content and structure directly from the web browser. In a typical wiki, text is written using a simplified markup language and often edited with the help of a rich-text editor.

A knowledge base (KB) is a technology used to store complex structured and unstructured information used by a computer system. The initial use of the term was in connection with expert systems which were the first knowledge-based systems.

Wikimedia Foundation American non-profit charitable organization

The Wikimedia Foundation, Inc. is an American non-profit and charitable organization headquartered in San Francisco, California. It is mostly known for participating in the Wikimedia movement. It owns the internet domain names of most movement projects and hosts sites like Wikipedia. The foundation was founded in 2003 by Jimmy Wales as a way to fund Wikipedia and its sibling projects through non-profit means.



Wikidata statements Mars.png
Three statements from Wikidata's item on the planet Mars. Values include links to other items and to Wikimedia Commons.
Wikidata layout Phase I.png
A layout of the four main components of a phase-1 Wikidata page: the label, description, aliases and interlanguage links.
Interlanguage links prior to Wikidata.png
A Wikipedia article's list of interlanguage links as they appeared in an edit box (left) and on the article's page (right) prior to Wikidata. Each link in these lists is to an article that requires its own list of interlanguage links to the other articles; this is the information centralized by Wikidata.
Interlanguage links provided by WikiData.png
The "Edit links" link takes the reader to Wikidata to edit interlanguage links.


Wikidata is a document-oriented database, focused on items, which represent topics, concepts, or objects. Examples of items include 1988 Summer Olympics (Q8470), love (Q316), Elvis Presley (Q303), and Gorilla (Q36611). Each item is identified by a unique number, prefixed with the letter Q, known as a "QID". This enables the basic information required to identify the topic the item covers to be translated without favouring any language.

A document-oriented database, or document store, is a computer program designed for storing, retrieving and managing document-oriented information, also known as semi-structured data.

Item labels need not be unique. For example, there are two items named "Elvis Presley": Elvis Presley (Q303) represents the American singer and actor, and Elvis Presley (Q610926) represents his self-titled album.

Elvis Presley American singer and actor

Elvis Aaron Presley, also known mononymously as Elvis, was an American singer and actor. Regarded as one of the most significant cultural icons of the 20th century, he is often referred to as the "King of Rock and Roll" or simply "the King".

<i>Elvis Presley</i> (album) 1956 studio album by Elvis Presley

Elvis Presley is the debut studio album by American rock and roll singer Elvis Presley. The album was released by RCA Victor, catalog number LPM-1254, in March 1956. The recording sessions took place on January 10 and January 11 at the RCA Victor recording studios in Nashville, Tennessee, and on January 30 and January 31 at the RCA Victor studios in New York. Additional recordings originated from sessions at Sun Studio in Memphis, Tennessee, on July 5, August 19 and September 10 of 1954, and on July 11, 1955.

Fundamentally, an item consists of a label, a description, and some number of statements.

This diagram shows the most important terms used in Wikidata Datamodel in Wikidata.svg
This diagram shows the most important terms used in Wikidata


Statements are how any information known about an item is recorded in Wikidata. Formally, they consist of key-value pairs, which match a property (such as "author", or "publication date") with one or more values (such as "Sir Arthur Conan Doyle" or "1902"). For example, the informal English statement "milk is white" would be encoded by a statement pairing the property color (P462) with the value white (Q23444) under the item milk (Q8495).

Statements may map a property to more than one value. For example, the "occupation" property for Marie Curie could be linked with the values "physicist" and "chemist", to reflect the fact that she engaged in both occupations. [8]

Marie Curie Polish-French physicist and chemist

Marie Skłodowska Curie was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. She was the first woman to win a Nobel Prize, the first person and only woman to win twice, and the only person to win a Nobel Prize in two different sciences. She was part of the Curie family legacy of five Nobel Prizes. She was also the first woman to become a professor at the University of Paris, and in 1995 became the first woman to be entombed on her own merits in the Panthéon in Paris.

Values may take on many types including other Wikidata items, strings, numbers, or media files. Properties prescribe what types of values they may be paired with. For example, the property official website (P856) may only be paired with values of type "URL". [9] Properties may also define more complex rules about their intended usage, termed constraints. For example, the capital (P36) property includes a "single value constraint", reflecting the reality that (typically) territories have only one capital city. Constraints are treated as hints rather than inviolable rules. [10]

Optionally, qualifiers can be used to refine the meaning of a statement by providing additional information that applies to the scope of the statement. For example, the property "population" could be modified with a qualifier such as "as of 2011". Statements may also be annotated with references, pointing to a source backing up the statement's content. [11]


In linguistics, a lexeme is a unit of lexical meaning. Similarly, Wikidata's lexemes are items with a structure that makes them more suitable to store lexicographical data. Besides of storing the language to which the lexeme refers, they have a section for forms and a section for senses. [12]

Wikidata Birthday Celebration at Kerala

Development history

The creation of the project was funded by donations from the Allen Institute for Artificial Intelligence, the Gordon and Betty Moore Foundation, and Google, Inc., totaling 1.3 million. [13] [14] The development of the project is mainly driven by Wikimedia Deutschland and was originally split into three phases: [15]

  1. Centralising interlanguage links – links between Wikipedia articles about the same topic in different languages
  2. Providing a central place for infobox data for all Wikipedias
  3. Creating and updating list articles based on data in Wikidata

Initial rollout

Wikidata was launched on 29 October 2012 and was the first new project of the Wikimedia Foundation since 2006. [5] [16] [17] At this time, only the centralization of language links was available. This enabled items to be created and filled with basic information: a label – a name or title, aliases – alternative terms for the label, a description, and links to articles about the topic in all the various language editions of Wikipedia.

Historically, a Wikipedia article would include a list of interlanguage links, being links to articles on the same topic in other editions of Wikipedia, if they existed. Initially, Wikidata was a self-contained repository of interlanguage links. Wikipedia language editions were still not able to access Wikidata, so they needed to continue to maintain their own lists of interlanguage links.

On 14 January 2013, the Hungarian Wikipedia became the first to enable the provision of interlanguage links via Wikidata. [18] This functionality was extended to the Hebrew and Italian Wikipedias on 30 January, to the English Wikipedia on 13 February and to all other Wikipedias on 6 March. [19] [20] [21] [22] After no consensus was reached over a proposal to restrict the removal of language links from the English Wikipedia, [23] the power to delete them from the English Wikipedia was granted to automatic editors (bots). On 23 September 2013, interlanguage links went live on Wikimedia Commons. [24]

Statements and data access

On 4 February 2013 statements were introduced to Wikidata entries. The possible values for properties were initially limited to two data types (items and images on Wikimedia Commons), with more data types (such as coordinates and dates) to follow later. The first new type, string, was deployed on 6 March. [25]

The ability for the various language editions of Wikipedia to access data from Wikidata was rolled out progressively between 27 March and 25 April 2013. [26] [27]

On 16 September 2015, Wikidata began allowing so-called arbitrary access, or access from a given Wikidata item to the properties of items not directly connected to it. For example, it became possible to read data about Germany from the Berlin article, which was not feasible before. [28] On 27 April 2016 arbitrary access was activated on Wikimedia Commons. [29]

Query service

On 7 September 2015, the Wikimedia Foundation announced the release of the Wikidata Query Service, [30] which lets users run queries on the data contained in Wikidata. [31] The service uses SPARQL as the query language. As of November 2018, there are at least 26 different tools that allow to query the data in different ways. [32]


In November 2014, Wikidata received the Open Data Publisher Award from the Open Data Institute “for sheer scale, and built-in openness”. [33]

As of November 2018, Wikidata information is used in 58.4% of all English Wikipedia articles, mostly for external identifiers or coordinate locations. In aggregate, data from Wikidata is shown in 64% of all Wikipedias' pages, 93% of all Wikivoyage articles, 34% of all Wikiquotes', 32% of all Wikisources', and 27% of Wikimedia Commons'. Usage in other Wikimedia Foundation projects is testimonial. [34]

As of November 2018, Wikidata's data is visualized by at least 20 other external tools [35] and at least 100 papers have been published about Wikidata. [36] Its importance has been recognized by numerous cultural institutions. [37]

The bars on the logo contain the word "WIKI" encoded in Morse code. [38]

See also

Related Research Articles

History of Wikipedia Historical development of Wikipedia

Wikipedia began with its launch on 15 January 2001, two days after the domain was registered by Jimmy Wales and Larry Sanger. Its technological and conceptual underpinnings predate this; the earliest known proposal for an online encyclopedia was made by Rick Gates in 1993, but the concept of a free-as-in-freedom online encyclopedia was proposed by Richard Stallman in December 2000.

The Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata data model. It has come to be used as a general method for conceptual description or modeling of information that is implemented in web resources, using a variety of syntax notations and data serialization formats. It is also used in knowledge management applications.

MediaWiki Wiki software

MediaWiki is a free and open-source wiki engine. It was developed for use on Wikipedia in 2002, and given the name "MediaWiki" in 2003. It remains in use on Wikipedia and almost all other Wikimedia websites, including Wiktionary, Wikimedia Commons and Wikidata; these sites continue to define a large part of the requirement set for MediaWiki. MediaWiki was originally developed by Magnus Manske and improved by Lee Daniel Crocker. Its development has since then been coordinated by the Wikimedia Foundation.

German Wikipedia German language edition of Wikipedia

The German Wikipedia is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia.

A semantic wiki is a wiki that has an underlying model of the knowledge described in its pages. Regular, or syntactic, wikis have structured text and untyped hyperlinks. Semantic wikis, on the other hand, provide the ability to capture or identify information about the data within pages, and the relationships between pages, in ways that can be queried or exported like a database through semantic queries.

Metadata management

Metadata management involves managing metadata about other data, whereby this "other data" is generally referred to as content data. The term is used most often in relation to digital media, but older forms of metadata are catalogs, dictionaries, and taxonomies. For example, the Dewey Decimal Classification is a metadata management systems developed in 1876 for libraries.

Wikimedia movement social movement around Wikimedia including content publications, Wikimedia organizations, and independent editors

The Wikimedia movement, or simply Wikimedia, is the global community of contributors to Wikimedia Foundation projects. The movement was created around Wikipedia's community, and has since expanded to the other Wikimedia projects, including the commons projects Wikimedia Commons and Wikidata, and volunteer software developers contributing to MediaWiki. These volunteers are supported by numerous organizations around the world, including the Wikimedia Foundation, related chapters, thematic organizations, and user groups.

Hungarian Wikipedia Hungarian-language edition of Wikipedia, the free encyclopedia

The Hungarian Wikipedia is the Hungarian/Magyar version of Wikipedia, the free encyclopedia. Started on July 8, 2003, this version reached the 300,000 article milestone in May 2015. As of 12 May 2019 this edition has 450,595 articles and is the 26th largest Wikipedia edition.

Semantic MediaWiki software for creating, managing and sharing structured data

Semantic MediaWiki (SMW) is an extension to MediaWiki that allows for annotating semantic data within wiki pages, thus turning a wiki that incorporates the extension into a semantic wiki. Data that has been encoded can be used in semantic searches, used for aggregation of pages, displayed in formats like maps, calendars and graphs, and exported to the outside world via formats like RDF and CSV.

Wikipedia Free online encyclopedia that anyone can edit

Wikipedia is a multilingual online encyclopedia with exclusively free content and no ads, based on open collaboration through a model of content editing using web-based applications such as web browsers, called wiki. It is the largest and most popular general reference work on the World Wide Web, and is one of the most popular websites by Alexa rank as of April 2019. It is owned and supported by the Wikimedia Foundation, a non-profit organization that operates on money it receives from donors to remain ad-free.

DBpedia online database project

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

History of wikis

The history of wikis is generally dated from 1994, when Ward Cunningham gave the name "WikiWikiWeb" to the knowledge base, which ran on his company's website at, and the wiki software that powered it. thus became the first true wiki, or a website with pages and links that can be easily edited via the browser, with a reliable version history for each page. He chose "WikiWikiWeb" as the name based on his memories of the "Wiki Wiki Shuttle" at Honolulu International Airport, and because "wiki" is the Hawaiian word for "quick".

Wikimedia Commons free-use media repository

Wikimedia Commons is an online repository of free-use images, sounds, other media and JSON files. It is a project of the Wikimedia Foundation.

Outline of Wikipedia Overview of and topical guide to Wikipedia

The following outline is provided as an overview of and topical guide to Wikipedia:

Volapük Wikipedia Volapük-language edition of Wikipedia

The Volapük Wikipedia is the Volapük-language edition of the free online encyclopedia Wikipedia. It was created in February 2003, but launched in January 2004. As of January 2017, it was the 59th-largest Wikipedia as measured by the number of articles, with about 123,000 articles, and the second-largest Wikipedia in a constructed language after the Esperanto Wikipedia.

Wikibase collection of software (applications and libraries) for creating, managing and sharing structured data

Wikibase is a set of MediaWiki extensions for working with versioned data in a central repository. Its primary components are the Wikibase Repository, an extension for storing and managing data, and the Wikibase Client which allows for the retrieval and embedding of structured data from a wikibase repository. Wikibase was developed for and is used by Wikidata.

Commercial use of Wikimedia projects refers to any business or product selling content from Wikipedia or Wikimedia projects which it freely took. Wikimedia projects use free and open copyright licenses which means that anyone may share the information for any purpose.


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  3. " Traffic, Demographics and Competitors - Alexa". Retrieved 4 February 2019.
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  9. "Help:Data type".
  10. "Help:Property constraints portal".
  11. "Help:Sources".
  12. "Wikidata - Lexicographical data documentation".
  13. Dickinson, Boonsri (March 30, 2012). "Paul Allen Invests In A Massive Project To Make Wikipedia Better". Business Insider. Retrieved September 11, 2012.
  14. Perez, Sarah (March 30, 2012). "Wikipedia's Next Big Thing: Wikidata, A Machine-Readable, User-Editable Database Funded By Google, Paul Allen And Others". TechCrunch. Archived from the original on September 11, 2012. Retrieved September 11, 2012.
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  16. Pintscher, Lydia (October 30, 2012). " is live (with some caveats)". wikidata-l (Mailing list). Retrieved November 3, 2012.
  17. Roth, Matthew (March 30, 2012). "The Wikipedia data revolution". Wikimedia Foundation. Archived from the original on September 11, 2012. Retrieved September 11, 2012.
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  19. Pintscher, Lydia. "Wikidata coming to the next two Wikipedias". Wikimedia Deutschland. Retrieved January 31, 2013.
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  31. "Announcing the release of the Wikidata Query Service".
  32. "Wikidata Query Data tools".
  33. "First ODI Open Data Awards presented by Sirs Tim Berners-Lee and Nigel Shadbolt". Archived from the original on 2016-03-24.
  34. "Percentage of articles making use of data from Wikidata".
  35. "Wikidata Tools - Visualize data".
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  37. "International Semantic Web Conference 2018".
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Further reading