Main page of Wikidata
Type of site
|Available in||multiple languages, Wikidatan|
|Founded||29 October 2012|
|Created by||Wikidata editors|
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,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.
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.
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.
Fundamentally, an item consists of an identifier, a label, a description, optionally multiple aliases, and some number of statements.
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). Properties, when paired with values, form a statement in Wikidata. Properties are also used in qualifiers. The most used property is instance of (P31), that is used on more than 53,000,000 item pages.
Properties have their own pages on Wikidata and are connected to items, resulting in a linked data structure.
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.
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".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.
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.
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.
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.The development of the project is mainly driven by Wikimedia Deutschland and was originally split into three phases:
Wikidata was launched on 29 October 2012 and was the first new project of the Wikimedia Foundation since 2006.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.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. After no consensus was reached over a proposal to restrict the removal of language links from the English Wikipedia, 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.
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.
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.
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.On 27 April 2016 arbitrary access was activated on Wikimedia Commons.
On 7 September 2015, the Wikimedia Foundation announced the release of the Wikidata Query Service,which lets users run queries on the data contained in Wikidata. 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.
In November 2014, Wikidata received the Open Data Publisher Award from the Open Data Institute “for sheer scale, and built-in openness”.
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.
As of November 2018, Wikidata's data is visualized by at least 20 other external toolsand at least 100 papers have been published about Wikidata. Its importance has been recognized by numerous cultural institutions.
The bars on the logo contain the word "WIKI" encoded in Morse code.
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 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.
SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It is particularly useful in handling structured data, i.e. data incorporating relations among entities and variables.
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 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.
The English Wikipedia is the English-language edition of the free online encyclopedia Wikipedia. Founded on 15 January 2001, it is the first edition of Wikipedia and, as of April 2019, has the most articles of any of the editions. As of March 2020, 12% of articles in all Wikipedias belong to the English-language edition. This share has gradually declined from more than 50 percent in 2003, due to the growth of Wikipedias in other languages. As of 29 March 2020, there are 6,044,222 articles on the site, having surpassed the 5 million mark on 1 November 2015. In October 2015, the combined text of the English Wikipedia's articles totalled 11.5 gigabytes when compressed.
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.
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.
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 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, and is one of the 20 most popular websites ranked by Alexa, as of March 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 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.
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 c2.com, and the wiki software that powered it. c2.com 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 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.
The following outline is provided as an overview of and topical guide to 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 60th-largest Wikipedia as measured by the number of articles, with about 124,000 articles, and the second-largest Wikipedia in a constructed language after the Esperanto Wikipedia.
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.
|Wikimedia Commons has media related to Wikidata .|
|Scholia has a topic profile for Wikidata .|
|Wikiquote has quotations related to: Wikidata|