Wikidata

Last updated
Wikidata
Wikidata-logo-en.svg
Wikidata main page (2019).png
Main page of Wikidata in November 2019
Type of site
Available inMultiple languages
Founded29 October 2012;7 years ago (2012-10-29)
Created byWikidata editors
URL www.wikidata.org OOjs UI icon edit-ltr-progressive.svg
Alexa rankDecrease Positive.svg 7,818 (January 2020) [1]
CommercialNo
RegistrationOptional

Wikidata is a collaboratively edited multilingual knowledge graph hosted by the Wikimedia Foundation. It is a common source of open data that Wikimedia projects such as Wikipedia can use, [2] [3] and anyone else, under a public domain license. The used data model is the Resource Description Framework. Wikidata is powered by the software Wikibase. [4]

Contents

Concept

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

Wikidata is a document-oriented database, focused on items, which represent topics, concepts, or objects. Each item is allocated a unique, persistent identifier, a positive integer prefixed with the upper-case letter Q, known as a "QID". This enables the basic information required to identify the topic that the item covers to be translated without favouring any language.

Examples of items include 1988 Summer Olympics (Q8470), love (Q316), Elvis Presley (Q303), and Gorilla (Q36611).

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.

But the label and the description text needs to be unique together. So, an Item is related with a unique identifier (QID). An identifier is linked to a pair: a label and a description, to dissolve any ambiguity.

Item types are general and lexemes.

Main parts

A layout of the four main components of a phase-1 Wikidata page: the label, description, aliases and interlanguage links. 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.

Fundamentally, an item consists of:

We are going to present them, from highest to lowest ones.

Statements

Three statements from Wikidata's item on the planet Mars (Q111). Values include links to other items and to Wikimedia Commons. Wikidata statements Mars.png
Three statements from Wikidata's item on the planet Mars (Q111). Values include links to other items and to Wikimedia Commons.

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 entity 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. [5]

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". [6]

Property and value

Example of a simple statement consisting of one property-value pair Simple statement - Earth.png
Example of a simple statement consisting of one property-value pair

A property describes the data value of a statement and can be thought of as a category of data, for example color (P462) for the data value blue (Q1088) or education for a person item.

As said, properties, when paired with values, form a statement in Wikidata. Values can include qualifiers.

The most used property is instance of (P31), that is used on more than 53,000,000 item pages. [7]

Properties have their own pages on Wikidata and as an item can include several properties, this results in a linked data structure of pages, under the same statement.

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 testing alerts and hints, rather than inviolable rules. [8]

Optionally, qualifiers can be used to refine the meaning of a statement by providing additional information that applies to the scope of the statement, within the values. For example, the property "population" could be modified with a qualifier such as "as of 2011". Values in the statements may also be annotated with references, pointing to a source backing up the statement's content. [9]

Lexemes

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 storing the language to which the lexeme refers, they have a section for forms and a section for senses. [10]

Development history

Wikidata Birthday Celebration at Kerala

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. [11] [12] The development of the project is mainly driven by Wikimedia Deutschland and was originally split into three phases: [13]

  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 and linking to other Wikimedia sister projects, including Wikimeta and the own Wikidata (interwikilinks).

Initial rollout

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 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.
The "Edit links" link nowadays takes the reader to Wikidata to edit interlanguage and interwiki links. Interlanguage links provided by WikiData.png
The "Edit links" link nowadays takes the reader to Wikidata to edit interlanguage and interwiki links.

Wikidata was launched on 29 October 2012 and was the first new project of the Wikimedia Foundation since 2006. [2] [14] [15] 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 (interwikipedia links).

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, mainly at the end of the articles' pages.[ citation needed ]

On 14 January 2013, the Hungarian Wikipedia became the first to enable the provision of interlanguage links via Wikidata. [16] 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. [17] [18] [19] [20] After no consensus was reached over a proposal to restrict the removal of language links from the English Wikipedia, [21] 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. [22]

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. [23]

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. [24] [25]

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. [26] On 27 April 2016 arbitrary access was activated on Wikimedia Commons. [27]

Query service and other improvements

On 7 September 2015, the Wikimedia Foundation announced the release of the Wikidata Query Service, [28] which lets users run queries on the data contained in Wikidata. [29] 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. [30]

On the other hand, in Wiktionary lateral pane, has been included "Wikidata item" in Tools, to help to create a new item and links for new pages, specially when the item is only in English Wiktionary and wants to link to othe Wikimedia project, rather than to Wiktionaries in other languages.

Reception

In November 2014, Wikidata received the Open Data Publisher Award from the Open Data Institute “for sheer scale, and built-in openness”. [31]

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. [32]

As of November 2018, Wikidata's data is visualized by at least 20 other external tools [33] and at least 100 papers have been published about Wikidata. [34] Its importance has been recognized by numerous cultural institutions. [35]

The bars on the logo contain the word "WIKI" encoded in Morse code. [36] It was created by Arun Ganesh and selected through community decision. [37]

Applications

See also

Related Research Articles

History of Wikipedia Historical development of Wikipedia

Wikipedia began with its first edit 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, and the concept of a free-as-in-freedom online encyclopedia was proposed by Richard Stallman in December 2000.

Interwiki links links between internet wikis

Interwiki linking (W-link) is a facility for creating links to the many wikis on the World Wide Web. Users avoid pasting in entire URLs and instead use a shorthand similar to links within the same wiki.

The Semantic Web is an extension of the World Wide Web through standards set by the World Wide Web Consortium (W3C). The goal of the Semantic Web is to make Internet data machine-readable. To enable the encoding of semantics with the data, technologies such as Resource Description Framework (RDF) and Web Ontology Language (OWL) are used. These technologies are used to formally represent metadata. For example, ontology can describe concepts, relationships between entities, and categories of things. These embedded semantics offer significant advantages such as reasoning over data and operating with heterogeneous data sources.

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.

SPARQL is an RDF query language—that is, a semantic query language for databases—able to retrieve and manipulate data stored in Resource Description Framework (RDF) format. It was made a standard by the RDF Data Access Working Group (DAWG) of the World Wide Web Consortium, and is recognized as one of the key technologies of the semantic web. On 15 January 2008, SPARQL 1.0 was acknowledged by W3C as an official recommendation, and SPARQL 1.1 in March, 2013.

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 engineers and 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 28 July 2020 this edition has 474,158 articles and is the 26th largest Wikipedia edition.

Semantic MediaWiki software for creating, managing and sharing structured data in MediaWiki

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 created and maintained as an open collaboration project by a community of volunteer editors using a wiki-based editing system. It is the largest and most popular general reference work on the World Wide Web. It is also one of the 15 most popular websites ranked by Alexa, as of August 2020. It features exclusively free content and no commercial ads and is owned and supported by the Wikimedia Foundation, a non-profit organization funded primarily through donations.

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 history of wiki collaborative platforms

The history of wikis begins in 1994, when Ward Cunningham gave the name "WikiWikiWeb" to the knowledge base, which ran on his company's website at c2.com, and the wiki software that powered it. The "wiki went public" in March 1995—the date used in anniversary celebrations of the wiki's origins. c2.com is thus 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.

Freebase was a large collaborative knowledge base consisting of data composed mainly by its community members. It was an online collection of structured data harvested from many sources, including individual, user-submitted wiki contributions. Freebase aimed to create a global resource that allowed people to access common information more effectively. It was developed by the American software company Metaweb and ran publicly beginning in March 2007. Metaweb was acquired by Google in a private sale announced 16 July 2010. Google's Knowledge Graph was powered in part by Freebase.

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 62nd-largest Wikipedia as measured by the number of articles, with about 125,000 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 semi-structured data in a central repository based upon JSON instead of the unstructured data of MediaWiki wikitext. 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.

References

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  6. "Help:Data type".
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  28. https://query.wikidata.org/
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  32. "Percentage of articles making use of data from Wikidata".
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Further reading