Wikidata is a free, collaborative knowledge base maintained by the Wikimedia Foundation that aims to centralize structured data about items and provide machine-readable data to Wikimedia projects and third parties. It contains over 15 million items with 48 million statements and is currently in the process of adding statements about items after initially linking language editions of Wikipedia articles. Wikidata utilizes a variety of tools to visualize and query its structured data.

1. A free knowledge base that can be read and
edited by humans and machines alike

2. What is WikiData?
● A project by Wikimedia Deutschland
● Launched October 2012
● An interlinked database representing
“the sum of all human knowledge”
● Centralising key data about “items”
● Serving data to other Wikimedia projects
● Serving machine-readable data to third parties
● MediaWiki extension (“WikiBase”)
● Fifth most active Wikimedia project!

3. Wikimedia Commons

4. Centralising file storage

5. Centralising key data storage

6. Phases of Wikidata
1.Language/project links (done for some)
2.Statements (in progress)
3.Queries and lists (planned)

7. Phases of Wikidata
1.Language/project links (done for some)
2.Statements (in progress)
3.Queries and lists (planned)
Currently in phase 2
● Wikipedia
● Wikivoyage
● Wikisource
● Wikimedia Commons (partial)
● Wikiquote

8. Phase 1 : Language links
● Old : Each Wikipedia article
contains links to all other
Wikipedia pages about the
same topic in different
languages

9. Phase 1 : Language links
● Old : Each Wikipedia article
contains links to all other
Wikipedia pages about the
same topic in different
languages
● New : WikiData contains links
to all Wikipedia pages about
an item
● ca. 250,000,000 language
links removed!

10. Items and “notability”
● All Wikipedia articles are automatically
“notable” on Wikidata
● Items can be created without associated
Wikipedia pages, if they either
– would be notable by Wikipedia standards
– serve a “structural need”

11. Items with statements
Label : One per item, per language Item ID: one unique identifier “Qxxx” per item
Description : One per item, per language
Alias : Multiple per item, per language

12. Items with statements
Label : One per item, per language Item ID: one unique identifier “Qxxx” per item
Description : One per item, per language
Alias : Multiple per item, per language
Statements : Multiple per item, per property
Links : One per item, per language/project

13. Phase 2: Statements
Statement
Property
Rank
Item reference
Qualifier(s)
Source(s)

14. Datatypes
Datatypes, depending on property:
● Item reference
● string
● time (precision: from billion years to the second)
● globe coordinate
● URL
● Quantity (numeric value&precision)
● Commons media
● Monolingual string

15. Browse in any language
English Chinese Scots

16. Using Wikidata in other
Wikimedia projects
● Show a statement value from the current
page's item in Wikipedia etc.
● parser function {{#property:PROPERTY}}
● scripts Lua mw.wikibase
● Usually “hidden away” in transcluded templates
● Popular on smaller Wikipedias

17. Metrics
● As of October 2014
● 15.8 million items (English Wikipedia: 4.6M articles)
● ~48 million statements
– 32.5 million item references
– 10.8 million strings
– 2.5 million dates
– 1.7 million coordinates
– 283K quantities
– 927 monolingual strings (those are new...)

18. Statements per item over time

19. WikiData API
● Extension of MediaWiki API
● Full-”text” search
● Request all statements/labels/links etc. for
individual items
● Editing via API
● OAuth bindings
● No queries for statements => items!

20. The Wikidata
tools ecosystem

21. WikiData Query
● Stand-alone WikiData query server
● Uses data dumps and Recent Changes, updated
every 10 minutes
● Keeps all item-to-item links, strings, times,
locations in RAM
● Can be queried over HTTP, returns JSON
http://wdq.wmflabs.org/

22. Query editor

23. People related to Queen Elizabeth II

24. GeneaWiki

25. AutoLists

26. Tempo-spatial
display
● Battles are “part of”
Franco-Prussian War
● Battles have date or
date range
● Battles have location
link or coordinates
● Some have an image

27. Reasonator
• Improved visualisation
• Special displays by item
type (maps for locations,
relatives for people)
• Uses statements from
related items
• Automatic description
• Iterates property trees
(location, species,
subclass)
• Timelines, auto-lists,
related images
• Quick info in item link
hoverboxes
• >100,000 views this month
tools.wmflabs.org/reasonator

28. Map of all WikiData items

29. URLs
WikiData http://www.wikidata.org
EtherPad
https://etherpad.wikimedia.org/p/LEskcETL2p

30. Concept cloud