Help:Data type

Data typesdefine how the statement will behave, and what kind of data they take. Different types of statements use different types of properties, and they are also using different data types. During creation of properties one of the choices is to set the data type, and once set the property gets locked to this data type. That has implications for how they can be used and there must be some amount of planning before a useful property can be defined.

Coordination of work on properties happens atWikidata:Property proposal.

Built-in data types

Data type	Number of properties
External identifier	8,941
Item	1,659
Quantity	658
String	333
URL	109
Commons media file	81
Point in time	67
Monolingual text	62
Property	21
Geographic coordinates	10
Tabular data	6
Geographic shape	3

Extra data types

Data type	Number of properties
Mathematical expression	36
Sense	19
Lexeme	15
Form	10
Musical Notation	6

Properties by type

For a list of the properties that currently require each type of data type, see either:

• Special:ListProperties
• List of all properties
• Constraint violations: all properties
• Category:Properties by datatype

Datatypes to link entities

Wikidata has 5 types of entities (Item,Property,Lexeme,SenseandForm). For each entity type there exists a same-named data type that can be used to link entities of that type.

Item

Link to anitem.(list of properties)

Property

Link to aproperty.(list of properties)

The following data types are primarily meant for statements on Lexemes, which make up thelexicographical dataof Wikidata.

Lexeme

Link to alexeme.(list of properties)

Form

For statements on lexemes that referenceformson other lexemes in order to indicate their relation.(list of properties)

Sense

For statements on lexemes that referencesenseson other lexemes.(list of properties)

EntitySchema

Link to aentity schema.(list of properties)

String-based data types

String

type:string (String)

list of properties:Category:Properties with string-datatype--Special:ListProperties/string

Chain of characters, numbers and symbols that don't need to be translated into different languages or number formats. A string is not used for calculations.

Examples:

• B123
• 90928390-XLE
• u29238

Maximum length is 1,500 characters on Wikidata, as defined withwmgWikibaseStringLimitsinInitialiseSettings.php.

Monolingual text

type:monolingualtext (Monolingual text)

list of properties:Category:Properties with monolingualtext-datatype--Special:ListProperties/monolingualtext

A string that is not translated into other languages. This type of string is defined once and reused in all languages. Typical use is a geographically localized entity name written in the local language, an identifier of some kind, a chemical formula or a Latin scientific name. SeeHelp:Monolingual text languagesfor information about the language codes available for monolingual text values and how to request support for additional language codes. (Note that monolingual text also implies a single script system, which can make the string somewhat problematic.)

Maximum length is 1,500 characters on Wikidata, as defined withwmgWikibaseStringLimitsinInitialiseSettings.php.

External identifier

type:external-id (External identifier)

list of properties:Category:Properties with external-id-datatype--Special:ListProperties/external-id

String that represents an identifier used in an external system. Will display as external link if aformatter URL(P1630)is defined. See:External identifiers.

Maximum length is 1,500 characters on Wikidata, as defined withwmgWikibaseStringLimitsinInitialiseSettings.php.

URL

type:url (URL)

list of properties:Category:Properties with url-datatype--Special:ListProperties/url

A generalized "URL" that identifies some kind of external resource, perhaps a link to an external site of some kind, or an identifier used for lookup in some kind of specialized resource.

Maximum length is 1,500 characters on Wikidata, as defined withwmgWikibaseStringLimitsinInitialiseSettings.php.

Data types to reference files on Commons

Commons media

type:commonsMedia (Commons media file)

list of properties:Category:Properties with commonsMedia-datatype--Special:ListProperties/commonsMedia

References to files on Wikimedia Commons. During entry in the textfield the "File" namespace on Commons will be searched for matching entries. These files can be used both to illustrate the concepts in Wikidata and as an actual property value for inclusion on Wikipedia.

Examples:

• Wikidata-logo.svg

Geographic shape

type:geo-shape (Geographic shape)

list of properties:Category:Properties with geo-shape-datatype--Special:ListProperties/geo-shape

Reference tomap datafile on Wikimedia Commons. During entry in the textfield the"Data" namespace on Wikimedia Commonswill be searched for matching entries.

Tabular data

type:tabular-data (Tabular data)

list of properties:Category:Properties with tabular-data-datatype--Special:ListProperties/tabular-data

Reference totabular datafile on Wikimedia Commons. During entry in the textfield the "Data" namespace on Commons will be searched for matching entries.

Data types for specific notations

Mathematical expression

type:math (Mathematical expression)

list of properties:Category:Properties with math-datatype--Special:ListProperties/math

Formatted string that displays as formula.

Example:

\sqrt{1-e^2}produces:${\sqrt {1-e^{2}}}$

Seew:Help:Displaying a formulafor applicable format.

Current limitation: input text can't be queried on Query Service.

Musical Notation

type:musical-notation (Musical Notation)

list of properties:Category:Properties with musical-notation-datatype--Special:ListProperties/musical-notation

Generated image in.png formatthat displays a musical score. Values for that data type are strings describing music followingLilyPondsyntax.

Example:

Value string\relative c' { c d e f | g2 g | a4 a a a | g1 |},produces

Other data types

Quantity

type:quantity (Quantity)

list of properties:Category:Properties with quantity-datatype--Special:ListProperties/quantity

A Quantity value represents a decimal number, together with information about the uncertainty interval of this number, and a unit of measurement. The attributes are:

• amount: the quantity's main value
• lowerBound: the quantity's lower bound (optional)
• upperBound: the quantity's upper bound (optional)
• unit: unit of measure item (empty for dimensionless values)

Internally, amount, lower bound and upper bound are strings; positive numbers are stored with a plus sign, though this will not be displayed. The representation of a quantity may not be longer than 127 characters; therefore, the maximal value of a quantity is 10^126-1.

Unit conversion is implemented based onconversion to SI unit(P2370).Most units with that property are normalized in the RDF export for the query service (October 2019).

The normalisation table is readable as a JSON filein the WMF Mediawiki repository.

Examples:

• 762 (dimensionless)
• 2500 km (upper and lower bounds are not set, with unit)
• 1.03 ± 0.02 g (enter asnominal value+/-tolerance,representing a lower and upper bound, with unit). The tolerance is in some cases not shown at Wikipedia, only the nominal value, for example in Wikidata lists produced by the listeria bot.

Time

type:time (Point in time)

list of properties:Category:Properties with time-datatype--Special:ListProperties/time

This data type stores a date in Gregorian or Julian calendar.See detailed structure.

Examples:

• 2012
• 1780-05 (=May 1780)
• 1833-11-01 (=1st November 1833)

SeeHelp:Datesfor more.

Globe coordinate

type:globe-coordinate (Geographic coordinates)

list of properties:Category:Properties with globe-coordinate-datatype--Special:ListProperties/globe-coordinate

A geographical position given as a latitude-longitude pair (in gms or decimal degrees) for a given "globe" (any stellar body). Globe defaults to "Earth" (globe:http://www.wikidata.org/entity/Q2). A "precision" parameter describes the resolution of the source of the coordinate. Note that the coordinate system is assumed to be "WGS84" (World Geodetic System 1984(Q11902211)), which may not be suitable for less Earth-like bodies, and this is not configurable.

Tracked inPhabricator
Task T56097

Currently, the Web UI of Wikidata doesn't expose all parameters of this data type. The value is visualized only as the coordinate, plus an embedded map if the globe isEarth(Q2).The precision can be modified in the edit mode. The globe is not visible, nor editable, in the item view. The full configuration is however visible in the history diff view (example).

Tracked inPhabricator
Task T250627

When using the Web UI, the value saved will be an exact multiple of the precision chosen.

It is possible to edit the data in full via API. TheCLI toolis one way to access the API. In this exampleOlympus Mons(Q520)is given a coordinate onMars(Q111)using the globe parameter (used incoordinate location(P625)):

wd ac Q520 P625 '{ "latitude": 18.4, "longitude": 226, "precision": 0.016666666666667, "globe": "http://www.wikidata.org/entity/Q111" }'

Theglobe.js scriptadds a UI to set the globe parameter ofcoordinate location(P625).

Bots such asLocatorBotmay detect when the globe parameter ofcoordinate location(P625)is not set according tolocated on astronomical body(P376).Addinglocated on astronomical body(P376)and waiting for a bot to update the coordinate globe is an accepted workaround.

Technical details

In theWikibase JSONformat each value is represented by"datatype": <datatype>, "datavalue": { "type": <type>, "value":...},where the representation of thevaluedepends on thetype.

In theRDFformat data types are represented by theRDF namein the following table prefixed withhttp://wikiba.se/ontology#(or thewikibase:prefix in case of the RDF dumps). Note that this prefix is also available in theWikidata query service,so for example?propwikibase:propertyType wikibase:Stringwill return all properties of data type String.

Name	JSONdatatype	RDF name	JSONtype	Implemented by	Links
Item	wikibase-item	WikibaseItem	wikibase-entityid	built-in	list,query
Property	wikibase-property	WikibaseProperty	wikibase-entityid	built-in	list,query
Lexeme	wikibase-lexeme	WikibaseLexeme	wikibase-entityid	WikibaseLexeme(Q28925815)	list,query
Sense	wikibase-sense	WikibaseSense	wikibase-entityid	WikibaseLexeme(Q28925815)	list,query
Form	wikibase-form	WikibaseForm	wikibase-entityid	WikibaseLexeme(Q28925815)	list,query
EntitySchema	entity-schema	EntitySchema	wikibase-entityid	Wikidata Entity Schema(Q73505550)	list,query
Monolingual text	monolingualtext	Monolingualtext	monolingualtext	built-in	list,query
String	string	String	string	built-in	list,query
External identifier	external-id	ExternalId	string	built-in	list,query
URL	url	Url	string	built-in	list,query
Commons media file	commonsMedia	CommonsMedia	string	built-in	list,query
Geographic shape	geo-shape	GeoShape	string	built-in	list,query
Tabular data	tabular-data	TabularData	string	built-in	list,query
Mathematical expression	math	Math	string	Math(Q21677559)	list,query
Musical Notation	musical-notation	MusicalNotation	string	Score(Q21678392)	list,query
Quantity	quantity	Quantity	quantity	built-in	list,query
Point in time	time	Time	time	built-in	list,query
Geographic coordinates	globe-coordinate	Globecoordinate	globecoordinate	built-in	list,query

Limitations

• Point in timedoesn't support time of day.phab:T57755
• Quantitydoesn't supportinfinity(Q205),e.g. you cannot stateprime number(Q49008)quantity(P1114)infinitely many.

Pending data types

For none of the following dates of implementation are likely to be available. Existing datatypes may solve it in the meantime.

See:Wikidata:Development plan

To be done

Duration

Tracked inPhabricator
Task T145532

time in HH:MM:SS format.

To plan

Calculated property

Tracked inPhabricator
Task T167521

A property calculated by Wikibase and added directly to items. Not in development plan.

Possible uses: number of statements on the item.

Celestial coordinates

Tracked inPhabricator
Task T127950

A coordinate format for specifying positions of celestial objects. Not in development plan.

Current work-around: seeWikidata:Property proposal/Astronomical coordinates

Integer datatype

Tracked inPhabricator
Task T112247

A quantity datatype for positive integer numbers. This was partially implemented by removing precision and creatinginteger constraint(Q52848401).

Monostring item

A datatype allowing descriptions in any language, but a single label. Not in development plan.

Current alternatives: lexemes

Alternative that is being evaluated: multilingual label replacing repeated labels

Multilingual text

Tracked inPhabricator
Task T86517

A string that must be translated into other languages. Use might be an entity name on non-local form, that is translated into various languages and script systems. (Note that multilingual text also imply a lot of manual work during translation.). Actual purpose to be determined.

Multiline text

Tracked inPhabricator
Task T323705

A string that may contain newlines.

Remote property

Tracked inPhabricator
Task T133381
Resolved

Properties in remote repositories are likely to be identified through a special field on existing entities, not a separate datatype.

Value series

Tracked inPhabricator
Task T147049

A simplified way to store series of values for different points in time. Not in development plan.

Chess

Tracked inPhabricator
Task T223460

Display strings in FEN notation as inposition in Forsyth-Edwards Notation(P6648)directly as chessboards.

Hiero

Strings for display withWikiHiero.Strings inWikiHiero syntaxare embedded in<hiero></hiero>to display. Samples onTalk:Q68101340andProperty_talk:P7383.

Phab request to do.

Combined human-readable and numeric id

Tracked inPhabricator
Task T260639

Datatype to add numeric id and page title, e.g. of a MediaWiki page. QualifierMediaWiki page ID(P9675)is sometimes added to property value with page titles. Some properties use the numeric value directly.

Wikibase statement

Tracked inPhabricator
Task T285157

Datatype to reference a specific Wikidata statement.

Regular expressions

Tracked inPhabricator
Task T244046

Datatype to store regular expressions (regex). These are currently stored as strings or monolingual text, e.g.format as a regular expression(P1793),format as language specific regular expression(P8770).

IP address ranges

Tracked inPhabricator
Task T235389

Datatype to store address ranges and simplify querying them.

Data types that will never be implemented

Boolean

Tracked inPhabricator
Task T145528
Declined

Declined. Suggested alternative: item-datatype.

Changing datatype

A property in "string" datatype may be converted to "external identifier" datatype by a system administrator. To propose such a change, you may start a discussion at the talk page of the property orProject chat.After a consensus, a request may be made inContact the development team.You should readprevious discussionif you want to convert a property created before 2016.

Other changes of data type requires creating a new property and deleting the old one. You should useProperties for deletionfor such requests.

See also

• Special:ListDatatypes
• Wikidata:WikiProject Properties/Reports/Datatypes
• Wikidata:Development plan