how to map other identifiers to Wikidata entity IDs - Wikidata

9 Nov 2015

In the article "Presenting Wikidata knowledge" [1], I've Been a bit Bold
and specified a recipe:

1. Find existing interesting wiki pages in the domain of your application.
2. View the Wikidata information for those pages, choose interesting
properties.
3. Associate Wikidata entity IDs with entities of your application.
4. Display their Wikidata information in the user's language.
5. Use the Wikidata "sitelinks" information about the item to provide links
to the full Wikipedia (and Wikiquote, Wikivoyage, etc.) article about the
entity in the user's language.

But I realize for something like a reference app there won't be Wikidata
items for every entity in your app for step 3: not every book in print has
a Wikidata item, nor does every musical recording, etc. For those there are
already identifiers such as ISBNs and "MusicBrainz release group ID"s (mmm,
brains). I assume reference app developers already use these more complete
identifiers and so I'm inviting them to add Wikidata entity IDs where
available.

I think these other identifiers are all "Wikidata property representing a
unique identifier" and there are about 350 of them [2] But surprisingly, I
couldn't find an easy way to look up a Wikidata item using these other
identifiers.

I found you can do it one-by-one in Wikidata Query [3] and in Wikidata
Query Serivce [4] but neither seems amenable to doing a query on the fly
"Get me the Wikidata item for each of these 100 ISBNs "2-7071-1620-3", ...

Also, is this a temporary thing? Will Wikidata eventually have items for
every book published, every musical recording, etc. and become a superset
of all those unique identifiers?

Thanks!

[1] https://www.mediawiki.org/wiki/API:Presenting_Wikidata_knowledge
[2] https://www.wikidata.org/wiki/Special:WhatLinksHere/Q19847637?limit=500
[2] https://wdq.wmflabs.org/api?q=string%5B957:"2-7071-1620-3"%5D and
[3] https://query.wikidata.org with the the SPARQL (mmm, sparkly)
PREFIX wdt: <http://www.wikidata.org/prop/direct/>

SELECT ?book WHERE {
   ?book  wdt:P957 "2-7071-1620-3"
}

-- 
=S Page  WMF Tech writer