Last modified: 2013-10-29 10:46:10 UTC
Items should support same-as (or kindof-pretty-much-the-same-as) relations to external IDs. Examples: * for publications: ISBN, DOI * for people: PND, OCLC * for proteins: UnitProt These could work a lot like site links (a list of domains-ID-pairs), but would have an important semantic difference: * sitelinks say "that page is about the same thing this item description is about" * external IDs say "this is another ID for the thing this description is about) External IDs often but not necessarily have a URL associated with them that can be used to get more information about the item from some other source. Ideally, there would be the same uniqueness-constraint on external IDs that we have for wikipedia links: only one item can have a given external ID, and each item can only have one ID from a given domain (realm). But this may be to restrictive to be practical, because granularity varies a lot between different identification systems.
Note that some (all?) of these aren't really unique, for example ISBN. This should be addressed somehow. Note also that this could be used for two-way linking to other sites like to Wikipedia, for example to OpenStreetMap. For example, a place could be linked with its node on OSM; if a label is changed on Wikidata, it could be pushed to OSM and if node coordinates are changed on OSM they could be pushed to Wikidata. This would open an entirely new can of worms regarding actions of users without an account...
This does not seem to be actually needed. Please reopen if a compelling use case comes up.
