Wikidata:External identifiers

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External identifiers are strings that represent identifiers used in external systems (databases, authority control files, online encyclopedias, etc.). They will display as external links in Wikidata items if a formatter URL (P1630) is defined.

IntroductionEdit

External identifiers link Wikidata items to databases, authority control files or encyclopedia articles about the item. Linking data to external sources can have many advantages for Wikidata:

  • Data quality: cross-checking statements with other, academic sources
  • Identifying missing notable items: by comparing Wikidata to other databases
  • Popularise and motivate the use of Wikidata: the maintainer of the external database can be notified that Wikidata is integrating their IDs, they can enrich Wikidata and their own data (See: Q24075706)
  • Supporting sister projects: for example providing references, further information links, etc., for Wikipedia

Properties for identifiersEdit

Required propertiesEdit

Property Description Example
instance of (P31) defines the type of external identifier
formatter URL (P1630) web page URL; URI template from which "$1" can be automatically replaced with the effective property value on items. If the site goes offline, set it to deprecated rank. If the formatter url changes, add a new statement with preferred rank
Multi-language sites: add the appropriate formatter for the different language URLs and use language of work or name (P407) as qualifier to specify the language and title (P1476) to add the name of the site in the particular language
VIAF ID (P214) --> formatter URL (P1630): https://viaf.org/viaf/$1
source website for the property (P1896) URL of website acting as source of data for this Wikidata property

Multi-language sites: add the appropriate URL for the different languages and use qualifiers language of work or name (P407) to specify the language

GND ID (P227) --> source website for the property (P1896): https://portal.dnb.de
format as a regular expression (P1793) regex describing an identifier or a Wikidata property. When using on property constraints, ensure syntax is a PCRE IMDb ID (P345) --> format as a regular expression (P1793): ev\d{7}\/\d{4}(-\d)?|(ch|co|ev|nm|tt)\d{7}

Properties related to source contentEdit

Property Description Example
language of work or name (P407) language(s) of the external ID's site Canadian Encyclopedia article ID (P5395) --> language of work or name (P407): English (Q1860), French (Q150)
applies to jurisdiction (P1001) the identifier contains items that are located in/related to the value (country, state, city, region, ....) Handbook of Texas ID (P6015) --> applies to jurisdiction (P1001) Texas (Q1439)
issued by (P2378) organisation that issues or allocates an identifier

Qualifiers: operator (P137): organization that operates the service

IMDb ID (P345) --> Internet Movie Database (Q37312)
subject item of this property (P1629) the database or other source that defines the identifier Fauna Europaea ID (P1895) --> Fauna Europaea (Q2745977)
see also (P1659) used to indicate another external ID that is similar in scope or topic Handbook of Texas ID (P6015) --> see also (P1659): Encyclopedia Virginia ID (P5981)
Wikidata usage instructions (P2559) text describing how to use a property or item ORCID iD (P496) --> Wikidata usage instructions (P2559): Four groups of four digits, separated by dashes ("-") (English)
expected completeness (P2429) describes whether a property is intended to represent a complete set of real-world items having that property Values:
URL match pattern (P8966) A regular expression that is supposed to match on a url that contains the id. It should also contain at least one group, that captures the id. Encyclopædia Britannica Online ID (P1417)^https?:\/\/www\.britannica\.com\/((?:topic|place|event|science|technology|plant|animal|biography|sports|art)(?:\/[^\s\/]+)+)

Formatter propertiesEdit

Property Description Example
mobile formatter URL (P7250) web page URL of mobile version; URI template from which "$1" can be automatically replaced with the effective property value on items Twitter username (P2002) --> mobile formatter URL (P7250): https://m.twitter.com/$1
third-party formatter URL (P3303) URI template from which "$1" can be automatically replaced with the effective property value on items; for sites other than the primary issuing body of the identifier concerned MusicBrainz artist ID (P434): http://www.bbc.co.uk/music/artists/$1. DOI (P356) has many third-party sites, Legal Entity Identifier (P1278) has some
search formatter URL (P4354) web page search URL; URI template from which "$1" can be automatically replaced with the string to be searched for ORCID iD (P496) --> search formatter URL (P4354): https://orcid.org/orcid-search/quick-search/?searchQuery=$1
formatter URI for RDF resource (P1921) formatter URL for RDF (semantic) resource: URI template from which "$1" can be automatically replaced with the effective property value on items (it is the URI of the resources, not the URI of the RDF file describing it) IdRef ID (P269) --> http://www.idref.fr/$1/id; Art & Architecture Thesaurus ID (P1014) --> http://vocab.getty.edu/aat/$1 (as opposed to http://vocab.getty.edu/page/aat/$1

Properties for documentation, usageEdit

Property Description Example
Wikidata property example (P1855) example where this Wikidata property is used; target item is one that would use this property, with qualifier the property being described given the associated value Tennessee Encyclopedia ID (P6016) --> Alfred A. Taylor (Q884027): alfred-alexander-taylor
corresponding template (P2667) the one-value-template that has the same meaning as this property Big Cartoon Database ID (P4933) --> corresponding template (P2667): Template:BCDB title (Q7169254)
property usage tracking category (P2875) category tracking a Wikidata property in sister projects Tennessee Encyclopedia ID (P6016) --> property usage tracking category (P2875): Category:Pages using Wikidata property P6016 (Q57953350)
property proposal discussion (P3254) URL of the page (or page section) on which the creation of the property was discussed ORCID iD (P496) --> property proposal discussion (P3254): https://www.wikidata.org/wiki/Wikidata:Property_proposal/Archive/7#P496
number of records (P4876) number of values of an identifier or records in a catalog GRID ID (P2427) --> number of records (P4876): 85,582

Properties for mapping, relationsEdit

Property Description Example
equivalent property (P1628) equivalent property in other ontologies (use property URI) IMDb ID (P345) --> http://purl.org/ontology/mo/imdb
has quality (P1552) use with component item if property is part of an other identifier Libraries Australia ID (P409) --> has quality (P1552): VIAF component (Q26921380), Qualifier: code (P3295): NLA
mix'n'match catalog ID (P2264) ID of the catalogue corresponding to the property in the mix'n'match tool Kunstindeks Danmark Artist ID (P1138) --> mix'n'match catalog ID (P2264): 91

ToolsEdit

WikiprojectsEdit