Wikidata

Last updated

Wikidata
Wikidata-logo-en.svg
Screenshot
Wikidata main page screenshot.png
Main page of Wikidata in April 2021
Type of site
Available inMultiple languages
Owner Wikimedia Foundation
EditorWikimedia community
URL www.wikidata.org OOjs UI icon edit-ltr-progressive.svg
CommercialNo
RegistrationOptional
Launched29 October 2012;10 years ago (2012-10-29) [1]

Wikidata is a collaboratively edited multilingual knowledge graph hosted by the Wikimedia Foundation. [2] It is a common source of open data that Wikimedia projects such as Wikipedia, [3] [4] and anyone else, can use under the CC0 public domain license. Wikidata is a wiki powered by the software MediaWiki, and is also powered by the set of knowledge graph MediaWiki extensions known as Wikibase.

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 any kind of topic, concept, or object. 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), Johnny Cash (Q42775), Elvis Presley (Q303), and Gorilla (Q36611).

Item labels need not be unique. For example, there are two items named "Elvis Presley": Elvis Presley (Q303), which represents the American singer and actor, and Elvis Presley (Q610926), which represents his self-titled album. However, the combination of a label and its description must be unique. To avoid ambiguity, an item's unique identifier (QID) is therefore linked to this combination.

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:

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]

Optionally, qualifiers can be used to refine the meaning of a statement by providing additional information. For example, a "population" statement 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. [7] As with statements, all qualifiers and references are property–value pairs.

Properties

Example of a simple statement consisting of one property-value pair Wikidata - simple statement.svg
Example of a simple statement consisting of one property–value pair

Each property has a numeric identifier prefixed with a capital P and a page on Wikidata with optional label, description, aliases, and statements. As such, there are properties with the sole purpose of describing other properties, such as subproperty of (P1647).

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]

Before a new property is created, it needs to undergo a discussion process. [9] [10]

The most used property is cites work (P2860), which is used on more than 280,000,000 item pages as of October 2022. [11]

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. [12]

EntitySchemas

In January 2019 development started of a new extension for MediaWiki to enable storing Shape Expressions in a separate namespace. [13] [14]

This extension has since been installed on Wikidata [15] and enables contributors to use Shape Expressions for validating and describing Resource Description Framework data in items and lexemes. Any item or lexeme on Wikidata can be validated against an Entity Schema, and this makes it an important tool for quality assurance.

Development

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. [16] [17] The development of the project is mainly driven by Wikimedia Deutschland under the management of Lydia Pintscher, and was originally split into three phases: [18]

  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 Meta-Wiki 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. [3] [19] [20] 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 (links to articles on the same topic in other editions of Wikipedia, if they existed). Wikidata was originally a self-contained repository of interlanguage links. [21] Wikipedia language editions were still not able to access Wikidata, so they needed to continue to maintain their own lists of interlanguage links.[ citation needed ]

On 14 January 2013, the Hungarian Wikipedia became the first to enable the provision of interlanguage links via Wikidata. [22] 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. [23] [24] [25] [26] After no consensus was reached over a proposal to restrict the removal of language links from the English Wikipedia, [27] they were automatically removed by bots. On 23 September 2013, interlanguage links went live on Wikimedia Commons. [28]

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. [29]

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. [30] [31] On 16 September 2015, Wikidata began allowing so-called arbitrary access, or access from a given article of a Wikipedia to the statements on Wikidata 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. [32] On 27 April 2016 arbitrary access was activated on Wikimedia Commons. [33]

According to a 2020 study, a large proportion of the data on Wikidata consists of entries imported en masse from other databases by Internet bots, which helps to "break down the walls" of data silos. [34]

Query service and other improvements

On 7 September 2015, the Wikimedia Foundation announced the release of the Wikidata Query Service, [35] which lets users run queries on the data contained in Wikidata. [36] The service uses SPARQL as the query language. As of November 2018, there are at least 26 different tools that allow querying the data in different ways. [37] It uses Blazegraph as its triplestore and graph database. [38] [39]

The bars on the logo contain the word "WIKI" encoded in Morse code. [40] It was created by Arun Ganesh and selected through community decision. [41]

Reception

In November 2014, Wikidata received the Open Data Publisher Award from the Open Data Institute "for sheer scale, and built-in openness". [42]

In December 2014, Google announced that it would shut down Freebase in favor of Wikidata. [43]

As of November 2018, Wikidata information was 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's. Usage in other Wikimedia Foundation projects is a testimonial. [44]

As of December 2020, Wikidata's data was visualized by at least 20 other external tools [45] and over 300 papers have been published about Wikidata. [46]

Wikidata's structured dataset has been used by virtual assistants such as Apple's Siri and Amazon Alexa. [47]

Applications

A systematic literature review of the uses of Wikidata in research was carried in 2019. [53]

See also

Related Research Articles

<span class="mw-page-title-main">History of Wikipedia</span>

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 1998.

The Semantic Web, sometimes known as Web 3.0, 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.

The Resource Description Framework (RDF) is a World Wide Web Consortium (W3C) standard originally designed as a data model for metadata. It has come to be used as a general method for description and exchange of graph data. RDF provides a variety of syntax notations and data serialization formats with Turtle currently being the most widely used notation.

<span class="mw-page-title-main">Wiktionary</span> Multilingual online dictionary

Wiktionary is a multilingual, web-based project to create a free content dictionary of terms in all natural languages and in a number of artificial languages. These entries may contain definitions, images for illustration, pronunciations, etymologies, inflections, usage examples, quotations, related terms, and translations of terms into other languages, among other features. It is collaboratively edited via a wiki. Its name is a portmanteau of the words wiki and dictionary. It is available in 186 languages and in Simple English. Like its sister project Wikipedia, Wiktionary is run by the Wikimedia Foundation, and is written collaboratively by volunteers, dubbed "Wiktionarians". Its wiki software, MediaWiki, allows almost anyone with access to the website to create and edit entries.

<span class="mw-page-title-main">MediaWiki</span> Free and open-source wiki software, used by Wikipedia

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

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.

<span class="mw-page-title-main">Wikimedia movement</span> Global community of contributors to Wikimedia Foundation projects

According to the Wikimedia Foundation, the Wikimedia movement is the global community of contributors to the Wikimedia projects. This community directly builds and administers the projects. It is committed to using open standards and software.

<span class="mw-page-title-main">Semantic MediaWiki</span> 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.

<span class="mw-page-title-main">Linked data</span> Structured data and method for its publication

In computing, linked data is structured data which is interlinked with other data so it becomes more useful through semantic queries. It builds upon standard Web technologies such as HTTP, RDF and URIs, but rather than using them to serve web pages only for human readers, it extends them to share information in a way that can be read automatically by computers. Part of the vision of linked data is for the Internet to become a global database.

<span class="mw-page-title-main">DBpedia</span> 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.

<span class="mw-page-title-main">History of wikis</span> History of wiki collaborative platforms

The history of wikis began 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".

<span class="mw-page-title-main">Wikimedia Commons</span> Online media repository of free-use images, sounds and other media files

Wikimedia Commons is a media repository of open images, sounds, videos and other media. It also contains 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 run publicly beginning in March 2007. Metaweb was acquired by Google in a private sale announced on 16 July 2010. Google's Knowledge Graph is powered in part by Freebase.

<span class="mw-page-title-main">Outline of Wikipedia</span> Overview of and topical guide to Wikipedia

Wikipedia is a free, web-based, collaborative and multilingual encyclopedia website and project supported by the non-profit Wikimedia Foundation. It has more than 48 million articles written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site, and it has about 100,000 regularly active contributors.

translatewiki.net, formerly named Betawiki, is a web-based translation platform powered by the Translate extension for MediaWiki. It can be used to translate various kinds of texts but is commonly used for creating localisations for software interfaces.

<span class="mw-page-title-main">Volapük Wikipedia</span> 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 15 November 2022, it is the 108th-largest Wikipedia as measured by the number of articles, with about 33,000 articles, and the second-largest Wikipedia in a constructed language after the Esperanto Wikipedia.

<span class="mw-page-title-main">Wikibase</span> MediaWiki software extensions

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.

<span class="mw-page-title-main">Denny Vrandečić</span> Croatian computer scientist

Zdenko "Denny" Vrandečić is a Croatian computer scientist. He was a co-developer of Semantic MediaWiki and Wikidata, the lead developer of the Wikifunctions project, and an employee of the Wikimedia Foundation as a Head of Special Projects, Structured Content. He published modules for the German role-playing game The Dark Eye.

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Further reading