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Wikidata:Glossary
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Elements of a statement, from itemQ42
This glossary defines important Wikidata concepts and refers to more detailed information. SeeWikidata:Introductionfor a general introduction into Wikidata and theglossary guidelinesfor how to write and improve glossary entries.
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Aliasis an alternative name for anitemor aproperty.In the user interface, it is sometimes labeled as "Also known as". The usual or most important name is thelabel.Aliases help people find an item even if they don’t search with the label. For example, the itemQ2has the label “Earth” and aliases such as “Tellus” and “Blue Planet”. It's a type ofterm. Further information:Help:Aliases
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Article placeholderis an extension to display stub articles and to start Wikipedia articles based on aviewof Wikidata items. Seemw:Extension:ArticlePlaceholder. |
Abadgeis an optional marker that can be attached to asitelinkto another Wikimedia page. For instance, a sitelink can be marked to link to a "featured article" or to a "proofread" page. Further information:Help:Badges
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Category item,template itemandmodule itemare Wikidata items withsitelinksto categories, templates, or modules on Wikimedia sites. When the last sitelink is deleted, these items are generally deleted (seeWikidata:Database reports/to delete). |
Claimis a piece of data about theentityon thepagewhere the claim appears. A claim consists of aproperty(such aslocation) and either avalue(e.g.,Germany) or one of the special cases "no value" and "unknown value". A claim can havequalifiers,such as temporal qualifiers saying that the claim is valid within a specific time frame. Compared totriplesin the RDF data model, a claim uses a property to express the predicate of a triple and a value to express the object of a triple. Claims form part ofstatementsonitempages, where they can be augmented withreferencesandranks.They can also occur on non-item data pages. |
Commons(orWikimedia Commons) is a Wikimedia project to store images, audio, video and other files. Wikibase includes three differentdatatypesto link from Wikidata to media files, geographic shapes and tabular data. Commons is adding statements to files asmediaentities. |
Completenessis an assessment of available data with a measure for coverage. At Wikidata the presence of an item or statement does not imply that all similar items or statements are present. Wikibase does not include any completeness indicator.Quantityproperties can be used to compare with available statements or items. Example: The item about states of the USA has a statement with quantity 50. One can compare that with the count of uses of the item. A few tools attempt to measure completeness. To some extent,property suggesterandsuggestion constraintsindicate elements missing to complete items. |
Complex constraint(orcustom constraint) is aconstraintdefined by a freely chosen SPARQL query in a template on a property talk page. Further information:Template:Complex constraint
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Conflationis a type of error, usually on an item, where aspects of several distinct concepts are mixed together. For example, an item with the date of birth of one person and the occupation of another person with the same name. Further information:Help:Conflation
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Constraintis a rule for how a particularpropertyshould be used. For instance most identifiers should have only one value, so there is asingle value constrainton them. A special kind are calledcomplex constraints. Further information:Help:Constraints
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Constraint reportcan refer to a series of periodically updated pages for each property based onconstraintsor aspecial pagefor an individual item or other entity. Further information:Wikidata:Database reports/Constraint violations
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Cradleis aneditingtool to create new Wikidata items based on a form with predefinedpropertiesandvalues. Further information:Wikidata:Cradle
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Datatype(orpropertyType) is an attribute of apropertyspecifying the type and shape of thevaluein eachclaim.Eachpropertyis assigned a pre-defined datatype, whichusuallycan not be changed. Not all values can be linked, as long as there are certain datatypes missing. Data types can only be defined by developers. See alsoSpecial:ListDatatypesfor currently available datatypes. Data type does not directly specify how values are stored internally; this is specified byvalue type. Further information:Help:Data type
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Data namespacesarenamespacesforpagesthat hold Wikidata entities. The data namespaces in Wikidata are themain namespacefor the Wikidataitems,"Property:"forproperties,and "Lexeme:"forlexemes. Further information:Help:Namespaces
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Date(ortimeortimeValue) is adatatypefor property values. It allows to enter dates in different precisions and enables date calculations in queries. Hour or minute precision isn't supported. TheWikidata property for the date of foundationhas such values. Further information:Help:Dates
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Descriptionis a language-specific descriptive phrase for anitemorproperty.It provides context for thelabel(for example, there are many items about places with the label "Cambridge"). The description therefore does not need to be unique, neither within a language or Wikidata in general, but it must be unique together with thelabel.Uniqueness for a combination of a label and a description is strictly enforced. If your edit does not meet this requirement you cannot publish it. It's a type ofterm. Further information:Help:Description
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Disambiguation itemis a Wikidata item withsitelinksto disambiguation pages. This is its only purpose. Generally, it has a claim withinstance of=Wikimedia disambiguation page. Further information:Wikidata:WikiProject Disambiguation pages
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Duplicateis anentity,generally an item, about the same concept as another entity. Duplicates are usuallymergedcreating aredirecting entity.Special types of duplicates aretemporary duplicates,permanent duplicates,andtrue duplicates. |
Editing interfaceis aviewthat allows to add or modify data. These views are the default view, the Commons structured data interface, Wikidata bridge, and a series of API-based tools, notablyQuickStatements,Cradle,PetScan, OpenRefine or thePywikibotframework. |
Entityis the content of a Wikidatapagein one of thedata namespaces,such as anitem(in themain namespace),property(in the Property namespace) orlexeme(in Lexeme namespace). Every entity is uniquely identified by anentity ID,which is a number with a prefix; for example, starting with the prefixQ for an item andP for a property. An entity is also identified by a unique combination oflabelanddescriptionin each language. An entity may have alternatealiasesin multiple languages (something similar to synonyms). Each entity has also adereferenceable URIthat follows the patternhttp:// wikidata.org/entity/ID whereIDis its entity ID.
Otherextensionsmay define new types of entities. For example:
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Entity selectorallows picking anentityby entering part of its name and selecting it from a list of search results. For items, the results are based on the labels and aliases. Thedescriptionis displayed, if there is one. Example: type "human" to pickQ1156970from "human (Q5) common name of Homo sapiens", "humanity (Q1156970) total world population of human", etc. This is different from theProperty Suggester. Further information:Help:Suggesters and selectors
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EntitySchemais a special type of Wikidatapagecontaining a document inShExformat, and related metadata. Although it may have labels, descriptions and aliases similar to items, it isnota type ofentity.Entities may be validated against an EntitySchema using theShEx2 — Simple Online Validator tool. Further information:Wikidata:Schemas Further information:Wikidata:WikiProject Schemas
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External identifieris a type of property — a string used in the database of external organizations. Some properties have external identifiers as values. Theyuniquely identifyan item, although the uniqueness is not enforced by software, but controlled byconstraint.For example, an ISBN for a book or the unique part of the URL of a movie or an actor in the Internet Movie Database. |
Federation queryis aquerythrough a service available onQuery Serverallowing to access databases other than Wikidata. Further information:Wikidata:SPARQL federation input
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Formis a string of characters that occurs in a particular grammatical context for alexeme.Every Lexeme may have multiple forms. Forms are identified on each lexeme by theLexeme IDfollowed by a dash, the letter "F" and a number. Forms may have statements just as other entities do. They are also assignedgrammatical featuressuch as "plural" for Form L1298-F2 ( "forms" ). A form is a type of anentity. Further information:Wikidata:Lexicographical data/Glossary
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Historic informationis included by qualifying it with adate.If information is no longer current, date qualifiers are added instead of statements overwritten. Historic information is different fromincorrect information |
Human(orinstance of human) is a Wikidata item about a person or an individual. It has a claim withinstance of=human. |
Incorrect informationis a claim supported by a reference, but generally considered invalid or inaccurate. While Wikipedia generally excludes such information, Wikidata's deprecatedrankallows to flag such statements. This helps avoid a situation in which it's deleted and erroneously re-added as valid information. Incorrect information is different fromhistoric information |
Instance of,subclass of,andhas part(alsoclassortype) are used on Wikidata to refer to the propertiesinstance of,subclass of,has part(s),and a few other related ontological properties, their values, or items using them. Further information:Help:Basic membership properties
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Itemrefers to a real-world object, concept, or event that is given an identifier in Wikidata together with information about it. Each item has a correspondingwiki pagein the Wikidatamain namespace.That page'stitleis the item's unique prefixedid,such as Q42. Every item may have human-readablelabelsanddescriptionsin multiple languages, but they are not necessarily unique. Items may also havealiasesto ease lookup. The main data part of an item is the list ofstatementsabout the item. An item can be viewed as the subject-part of atripleinlinked data.An item is a type of anentity. Further information:Help:Items
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Item identifier:seeQIDbelow. |
Labelis the main name given to anitemor aproperty.E.g. the item with theitem identifierQ7378has the English label “elephant”. An entity may have one label in each given human language. Labels do not need to be unique.Descriptionsandaliasesare used to distinguish between entities with the same label. A label of aWikidatapageis automatically displayed in the user interface language in front of itsid(e.g. "elephant(Q7378)"). A label doesnotuniquely identify the page; this function is served by itsQID(title)only. The label is a type ofterm.In English, labels should generally follow the English languagecapitalization rules:uppercase should only be used inproper nouns. Further information:Help:Labels
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Lagordatabase lagat Wikidata is a delay in the update of data on other projects orQuery Server. |
Language attributesare the language-specificlabels,aliasesanddescriptionsthat are assigned toitems,propertiesandqueries.These are human-readable text to improve understanding of the scope of the item; for example, the specific type of real world entity. If they are missing, some of them can be replaced by strings from alternate languages, following thelanguage fallback chains. |
Language codeis an identifier for the language of a label, description, alias, or monolingual text value. The language codes for labels, descriptions, and aliases are shared with other Wikimedia projects. More codes for monolingual text are defined specifically for Wikidata. Lexemes use some of these, as well as some additional codes or items to identify the language in lemma, gloss, and form. A language code is also assigned to sitelinks. Codes are based mostly onIETF language tags. Further information:Help:Monolingual text languages
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Language fallbacks(alsolanguage chains) are methods to systematically replace missinglanguage attributeswith strings from alternate languages. The exact replacement rules can be chosen depending on the type of page, whether the user is logged in, or the user preferred languages. |
Lexemeis anentityofLexicographical data.A lexeme may contain sense and form entities, but no sitelinks. Instead of a label, a description, and aliases, lexeme entities have a lemma (possibly more than one, for languages with spelling variants), a language, and a lexical category. Further information:Wikidata:Lexicographical data/Glossary
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LID(orL number) The identifier for alexemeentityin Wikidata, comprising the letter "L" followed by one or more digits. |
Listeria(orWikidata list) is a tool toshowdata from Wikidata in list form at Wikimedia projects. Data is periodically updated by bot. Further information:Template:Wikidata list
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Mainspaceis one of thenamespacesin a wiki. Namespaces in Wikidata other than the mainspace have prefixes. In Wikidata, the mainspace contains the pages with theitems. Further information:Help:Namespaces
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MediaWikiis the software that runsWikidata,Wikipedia and otherwikis.The MediaWiki installation of Wikidata makes use of theWikibaseextension. Further information: [[{{{1}}}]] What is MediaWiki?
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MediaInfois a type ofentityused to describe files. It's activated on Wikimedia Commons. |
Meta pagesThese are all the pages that are notentities,which means that they do not belong to thedata namespaces.Wikidata meta pages contain unstructured content in wikitext, including Wikidataclientsideinclusioncode. Examples aretalk pages,category pages,project pages(in the Wikidata namespace) andhelp pages(in the Help namespace). Meta pages also comprise content and data automatically generated by the MediaWiki software (for example, the edit history of apage,orspecial pages). |
Name itemis a Wikidata item about a given name or a family name. Such items are used as values forfamily nameorgiven nameand can include additional information and sitelinks. Further information:Wikidata:WikiProject Names
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Namespacesare a kind of category for pages in a wiki. For each namespace you may have different rules about the pages and their content. In Wikidata, the most important namespace (or ‘main namespace’) is for the Wikidataitems.The URL of a Wikidata mainspace page ends with aQ and a number, for example,Q7378for “Elephant”. The pages in other namespaces start with the namespace name, the “prefix”. For example, help pages start with “Help:”,such asHelp:Contents.Further information:Help:Namespaces
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ObjectSeeSubject |
Order of statementsis generally determined by theviewbeing used and not significant. Many views display data retrieved or entered first before other. Some views sort or allow to sort statements based on qualifier value, statement value, property, or datatype. |
Pageis an internal or external webpage with a uniquetitle,for example, anarticlein Wikipedia main namespace or anitemin Wikidata main namespace. A page is a part of a site. In Wikidata, the term "page" may refer to anitemor apropertypage in thedata namespaces,to ameta pagein other namespaces, or to an externallinked pageon Wikipedia, another Wikimedia site, or an external site. A page on a client site may be referenced using asitelink.Pages in the main namespace of Wikidata containitems,and one page can only hold one item. |
PredicateSeeSubject |
PrefixUsed in thequery service. Further information:mw:Wikibase/Inde xing /RDF Dump Format/Prefixes Further information:EntitySchema:E49
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Projectis a term often used in theWikimediamovement to refer to a Wikimediawiki.In Wikidata, the term usually refers toWikidataitself. |
Propertydescribes the data value of astatementand can be thought of as a category of data, for example, "color" for the data value "blue". Properties, when paired withvalues,form a statement in Wikidata. Properties are also used inqualifiers.Properties have their own pages on Wikidata and are connected toitems,resulting in a linked data structure. A property is a type of anentity Further information:Help:Properties
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Property suggesterprovides a preselection ofpropertieswhen adding statements to Wikidata items. These are based on the frequency of the properties on similar items. Example: on an item withinstance of=humanonly, suggestions could besex or gender,occupation,date of birth.These may or may not be appropriate for the specific item. This is different fromentity selectorandsuggestion constraints. Further information:Help:Suggesters and selectors
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QID(orQ number) is theunique identifierof a dataitemon Wikidata, comprising the letter "Q" followed by one or more digits. It is used to help people and machines understand the difference between items with the same or similar names. For example, there are several places in the world called London and many people called James Smith. This number appears next to thelabelat the top of each Wikidata item. |
Qualifieris a part of theclaimthat says something about the specific claim, often in a descriptive way. A qualifier might be a term according to a specific vocabulary but can also be a variant descriptive phrase (whether those terms or phrases are free text or part of some vocabulary would probably be up to the Wikidata community). Further information:Help:Qualifiers
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Quantity(incorrectlynumber) is adatatypefor property values. It allows to enter integers or decimal numbers. Optionally aunitor a bound can be included. TheWikidata property for populationhas such values. Numeric identifiers are not quantities, butexternal identifiers. Further information:Help:Data type#Quantity
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Queryis a search acrossitemsin Wikidata and their associated data. Queries are usually executed on theWikidata Query Serviceusing the SPARQL query language. Further information:Wikidata:SPARQL query service/Wikidata Query Help
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QuickStatements(QS) is a third-party tool that can edit Wikidata items, based on a simple set of text commands. The tool can add and remove statements, labels, descriptions, and aliases. It can also add statements with optional qualifiers and sources. Further information:Help:QuickStatements
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Rankis a quality factor used for simple selection and filtering in cases where there are severalstatementsfor a given property. In such cases, you may want to indicate which statement is more important or relevant than other statements. By default, a statement has the rank "normal", but you can change this to either "preferred" or "deprecated". "deprecated" rank can be used for statements supported by a reference, but considered incorrect. Further information:Help:Ranking
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Redirecting entity(orredirect) is anitemor alexemethat redirects to another item or lexeme (target). As in many uses these would need to be queried specifically, a bot usually replaces redirects used as values with their target. Further information:Help:Redirects
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AReference(orsource) is used to point to a specific resource that supports aclaiminWikidata.A reference can be a link to a URL or anitem;for example, an item about a book. Wikidata does not aim to answer the question of whether a claim is correct, but only whether the claim appears in a reference. A claim together with the reference form astatement. Further information:Help:Sources
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Repurposingis changing the definition or scope of anentity,in general an item, by editing its label, description or statements. Generally to be avoided. |
Sandboxorsandbox itemsare series of items, properties and other entities at Wikidata to test features within the Wikidata live database. Examples: itemQ4115189,propertyProperty:P369,EntitySchemaEntitySchema:E123,lexemeLexeme:L123. |
Senserefers to a specific meaning for alexeme.Senses are identified on each lexeme by theLexeme IDfollowed by a dash, the letter "S" and a number. Senses may have statements just as other entities do. They also allow a "gloss": a free-form description of the meaning (one per language). A sense is a type of anentity. Further information:Wikidata:Lexicographical data/Glossary
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Siteis a reference to an external website in general, but insitelinksit refers to specific registered wikis, for example, a Wikipedia language version. Those sites are referenced by site identifiers, or for shortsiteids, technically corresponding to the wiki'sDBname.For example, the Latin Wikipedia's siteid islawiki .Each externalpagecan have only one link registered in Wikidata and oneitemcan only have one link to each external site.
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Sitelinkis an identification of a linked page on another site. It consists of asite identifierand atitle,and is stored in individualitemsin Wikidata. Sitelinks are used both for identifying an item from an external site, and as a central storage of interlanguage links (sometimes known as "interwiki links", although this term also has a different meaning). Further information:Help:Sitelinks
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Sitelinks between Wiktionary editionsare generally not provided through Wikidata, but another function. Further information:Wikidata:Wiktionary/Sitelinks
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Snakis a technical term ofWikibasesoftware which data users are most likely to encounter whenaccessing Wikidata through the MediaWiki API.It refers to the combination of apropertyand either avalueor one of the special cases "no value" and "unknown value". Snaks can be found inclaims(then they are calledmain snaks) or inqualifiersas part ofstatements(then they are calledqualifier snaks). E.g., in the statement "Emma Watson was a cast member ofHarry Potter and the Philosopher's Stonein the role of Hermione Granger "there is a main snak" was a cast member of Harry Potter and the Philosopher's Stone "and a qualifier snak" in the role of Hermione Granger ". |
AStatementis a piece of data about anitem,recorded on the item'spage.A statement consists of aclaim(a property-value pair such as "Location: Germany", together with optional qualifiers), augmented byreferences(giving the source for the claim) and arank(used to distinguish between several claims containing the same property; "normal" by default). Wikidata makes no assumptions about the correctness of statements, but merely collects and reports them with areferenceto a source. The term "statement" is often used interchangeably with "claim",but technically it only becomes a statement once at least one reference has been added. Further information:Help:Statements
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String(alsocharacter string) is a general term for a sequence of freely chosen characters interpreted as text like "Hello", as opposed to a value interpreted as a numerical value (like 3.14) or a link to an item (like[[Q1234]] ). In addition to a stringdatatype,Wikidata supports language-specific texts using "monolingual-text" as thevalueof a property.
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Subject,predicateandobjectare terms sometimes used to describe aclaimwhen viewingentity,propertyandvalueas atriple. |
Suggestion constraintis a status of a propertyconstraintthat provides suggestions of additional improvements. This can be statements with other properties to be added to the item. |
Termis a part ofentity,includeslabel,descriptionandalias.Terms may only be plain text, which means that they cannot contain any wiki markup. |
Termboxis the zone at the top of an item page, which includes the labels, the descriptions, and the aliases in different languages. |
Titleis the name of apage.All pages must have a unique title within a givenwiki,as the title is included in the URL for the page. For example, there can be only one page with the title "Douglas Adams" on English Wikipedia. In Wikidata, a title is either anentity identifiersuch asQ42,or it starts with anamespaceprefix such asHelp: .The page title is not to be confused with thelabelfor a Wikidata item or property. Wikidataitemsare connected to pages on otherWikimedia wikisviasitelinks,which use the page's title to uniquely identify the resource.
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Triple(or "semantic triple",or" triplet ") is the atomic data entity in the RDF data model, which codifies statements in the form of subject–predicate–object expressions. |
Unitis a Wikidata item used with aquantity-value. Frequently used units are metre or EUR, but any item could be used as unit. If the unit includes aconversion to SI unitstatement, quantities with the unit are normalized based on that. Seemw:Wikibase/Inde xing /RDF Dump Format#Normalized values. |
Value(alsodatavalue) is the actual piece of information stored within aclaim.Wikidata has a range of alloweddatatypes,such as "item", "mathematical expression", and "quantity". The datatype needed for any given claim is determined by the property used (e.g. the value in a "place of birth" claim must be an "item" ). Instead of a normal value, you can also use one of the special cases "unknown value" or "no value" in a claim. Further information:Help:Statements
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Value typeis the wayvaluesare stored internally. Eachdata typecorresponds to one value type. For example, although external identifier, Commons media and mathematical expression are different datatypes, they all use the "string" value type. Values for some data types contain multiple parts with different value types. For example, a quantity contains four parts: "amount", "unit", "upperbound" and "lowerbound", the last two being optional. Unit is a URL which points to a Wikidata item; the other three parts are numbers in string (not floating-point number). |
Viewis a way data can be visualized or accessed. Besides the default view, Wikibase offers views for mobile devices, as well as for rdf and json formats. The data can be accessed with an API. Data on Wikidata is mirrored onWikidata Query Serveroffering various result views. Some of the views areediting views,others not. Examples of tools and extensions that provide custom views areReasonator,Article Placeholder,andListeria. Further information:Wikidata:Data access Further information:Wikidata:How to use data on Wikimedia projects Further information:Wikidata:SPARQL query service/Wikidata Query Help/Result Views
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Wikibaseis the software behind Wikidata. It consists of a set of extensions to theMediaWikisoftware. These extensions allow Wikidata to manage data initemsandproperties,and search for this data usingqueries. Further information:Help:Wikibase
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Wikidatais a Wikimedia project that runs an instance ofMediaWikiwith theWikibase extensions.It enablesWikidata editorsto enter data and browsepagesthat display it. Further information:Wikidata:Introduction
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Wikidata Query Service(orWDQS) is the official service forqueryingWikidata using the SPARQL query language. Further information:Wikidata:SPARQL query service/Wikidata Query Help
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Wikimediais the name of a movement which consists of people and organizations. Wikidata is run by the Wikimedia Foundation together with otherwikissuch as Wikipedia. TheWikibasesoftware is mainly developed by Wikimedia Germany which is one of the national Wikimedia affiliations. Further information:Help:Wikimedia
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Wikiis a website that can be edited by the visitors quickly. Wikipedia and Wikidata are wikis. Further information:Help:Wiki
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