Wikidata

Wikidata (.org) is an effort to store and serve structured data to Wikimedia wikis and to a more limited extent to other parties. Wikidata was started in 2012. The software developed is known as the Wikibase extension.

Wikibase allows interwiki links to be managed with Wikidata removing much contributor annoyanges, redundancy and error-proneness.

Obviously a main source of reference level data.

It can be accessed outside of WMF wikis with with

• SPARQL Wikidata advice on how to query their endpoint https://query.wikidata.org/
• mw:Wikidata Toolkit is a way for Java programs to access data in the Wikidata repository.
• SPARQL Endpoint interface to Python

More info

• Metawiki on Wikidata
• Wikipedia article on Wikidata
• Wikipedia advice on Wikidata issues

Main entry point of any Wikidata item is a JSON dictionary, that has this form:

{“labels”: by-language dictionary

“descriptions”: by-language dictionary

“aliases”: by-language dictionary

“claims”: list of property and values

“sitelinks”: by-language dictionary}

See also

• Database for a higher level view of what is going on with the databases
• Semantic MediaWiki is system for inputting and querying semantic data within the MediaWiki and it is implemented as extension(s).
• DBpedia the original structured data harvesting effort for the MediaWiki wikis