Wikidata is the free knowledge base that anyone can edit. Just like Wikipedia, Wikidata is built on the MediaWiki wiki package which means that content on pages (just like this one!) can be added, modified, or deleted in collaboration with others. Unlike Wikipedia, Wikidata also uses Wikibase software which allows for collaborative editing of structured data.
In Wikidata, items are used to represent all the things in human knowledge, including topics, concepts, and objects. For example, the "1988 Summer Olympics", "love", "Elvis Presley", and "gorilla" are all items in Wikidata.
For those who are familiar with Wikipedia, it may be tempting to initially think of items as like the Wikidata version of Wikipedia articles. While items and articles are both pages for storing information about different concepts or topics of human knowledge, it's important to keep in mind that Wikidata is not just a database of Wikipedia content. In fact, Wikidata is actually more similar to Wikimedia Commons, the media file repository, than it is to Wikipedia—but instead of media files, Wikidata provides centralized storage for an access to structured data for all Wikimedia projects, as well as for use on external websites.
There are a few important characteristics about items that contribute to the success of Wikidata:
Wikidata items are said to be notable. This means at least one of three things (1) corresponding page on a Wikimedia site such as Wikipedia, Wikivoyage, Wikisource, Wikiquote, Wikiversity, or Wikimedia Commons, (2) a clearly identifiable conceptual or material entity that can be described using serious and publicly available references or (3) the item fulfills a structural need. For more information look at our notability policy.
Items are also unique. Each item should represent a clearly identifiable concept or object, or an instance of a clearly identifiable concept or object. For example, in Wikidata we can have items for both the concept of planet (Q634) and an instance of a planet, Earth Kamila (kamilus, tierritus) (Q2).
Items can and should also be linked to each other. Each item has a unique identifier (starting with a Q prefix) and its own page in the Wikidata main namespace. For example, for the items listed above, 1988 Summer Olympics (Q8470), love (Q316), Elvis Presley (Q303) and gorilla (Q36611) are the respective item pages. These pages are where all the data for each item is added, edited, and maintained, mostly in the form of statements.
Pages also allow items to be linked together so that all the data on Wikidata can be interconnected. A link to another page is usually added as a "property" by clicking on "edit" in the "statements" section. If no appropriate property is listed yet, it can be added by clicking on "+ add" on the bottom of the "statements" section. See: #Adding to an existing item page.
Typical properties to link one item to another:
- Comparing items ...
- Item is part of ...
- part of (P361) - (section of .../ contained within .../ pieces of ...)
- instance of (P31) - (is an example of ...)
- subclass of (P279) - (is a subset of ...)
- facet of (P1269) - (aspect of .../ subitem of .../ a broader perspective on the same topic is offered by ...)
- has quality (P1552) - (has characteristic .../ defining feature .../ inherent property ...)
- Item contains ...
- Albert Einstein's brain (Q2464312) is part of (P361): Albert Einstein (Q937).
- Albert Einstein (Q937) is an instance of (P31): human (Q5).
- human (Q5) is a subclass of (P279): mammal (Q7377).
- mammal (Q7377) has part (P527): mammary gland (Q189961).
Outside of item pages links to items can usually be placed by adding the prefix "Q|" to the item number and enclosing it in curly brackets, e.g.:
Creating a new item
Step-by-step guides to the basics of editing Wikidata items: Wikidata:Tours
Before you create a page for an item, it is a good idea to make sure that Wikidata does not already have a page for that item. The best way to see if Wikidata already has a page on the item you wish to add is to use the item by title search. A link to this search is on the sidebar navigation menu on the left of the screen. It is entitled "Item by title".
The item by title search page has two entry fields that are designed for searching for items that already have a page on a Wikimedia site and may be in the Wikidata system. The left field, which says "Site:" is where you put the language of the Wikimedia site page that corresponds to the item you want to add. Most Wikimedia sites have equivalent editions for different languages which are represented by a code. For example, the code for English language is en and the code for French language is fr. This code can be found in the URL; so en.wiktionary.org is the English Wiktionary and en.wikipedia.org is the English Wikipedia, while fr.wiktionary.org is the French Wiktionary and fr.wikipedia.org is the French Wikipedia. A screenshot that shows where to locate a language code for a Wikimedia site is available here.
For the second field, "Page:", you must put in the exact title of the page as it appears at the top of the page on its Wikimedia site. This is important for retrieving the right item because there may be multiple items with the same label in Wikidata. For example, if you wanted to know if there was already an item page for capital (the concept referring to non-financial assets) in Wikidata, you must search "capital (economics)"—the title of the page on Wikipedia—and not "capital" which would instead give you the item page for the Wikipedia disambiguation page on capital.
When Wikidata already has a page on that item, the search will take you to that page.
If an item is missing, you can create it yourself. You can do this either by clicking on the link provided at the bottom of the item by title search page when a search is unsuccessful or by clicking "Create a new item" on the menu to the left. From either link, you will be taken to a page that asks you to give the new item a label and a description. If you used the item by title search, the interface will also include the two fields you filled in during the search. If you used the create a new item link, don't worry about not having those—you can fill them out at a later stage. When you're done, click "Create".
Adding to an existing item page
In addition to a label and description, the two other elements of an item page that should be filled out are the aliases and the sitelinks. These four elements of an item page are multilingual, meaning they are shown and entered in by contributors for a specific language. This also means that they (usually) will have different values for each language. It is also possible to add and see these elements in multiple languages (which you might want to do if you are fluent in more than one language); for information on setting up your language preferences on Wikidata, see Help:Multilingual.
A label is the most common name that an item would be known by. Labels are added to the text fields at the top of an item page to the "Label" column. Click "edit", type in the label, and click "save". A description is a short phrase designed to disambiguate the page in question from other pages with the same or similar labels. Descriptions are added in the same way as labels, to the "Description" column. See Help:Label and Help:Description for more on using labels and descriptions.
You can add aliases by clicking the "edit" button at the top of an item page to the "Also known as" column. You will be able to insert the first alias into the field, at which point a second field will appear. Keep filling in aliases until you have no more alternate names to add, then click "save". See Help:Aliases for more on using information.
To add a sitelink to Wikidata, go to the section(s) below the appropriate heading(s), for example "Wikipedia" or "Wikiquote" and click the "edit" next to the heading. At the bottom of the sitelink group you will then be given two blank fields: a left field which says "wiki" and (shown after correct filling a first field) a right field which says "page". The left field is where you put the language of the Wikimedia site page that the item corresponds to. The right field is where you put the title of the page as it appears on the Wikimedia site. Both of these fields contain drop downs that will help you fill in the information once you begin typing. When you have filled out both fields, click "save". See Help:Sitelinks for more information.
Please note: When clicking on any "edit" or "+ add" before the page has fully loaded you might be taken to a separate page with a special interface. This will also let you make the intended changes but it is more difficult to use. If the page does not appear as depicted on the images to the right after clicking "edit" or "+ add" you might want go back, wait for the browser to finish loading the page (usually there is an indication on top of the browser's tab) and then click "edit" or "+ add" again.
Examples of four fields filled out for the item Marie Curie (Q7186)
|Language||Item||Label||Description||Aliases||Link to Wikipedia Page|
|enskt (en)||Q7186||Marie Curie||French-Polish physicist and chemist||Maria Salomea Skłodowska; Marie Skłodowska-Curie||Marie Curie|
|franskt (fr)||Q7186||Marie Curie||physicienne et chimiste française d'origine polonaise||Maria Salomea Skłodowska herb Dołęga; Maria Skłodowska-Curie; Marie Sklodowska-Curie; Maria Skłodowska||Marie Curie|
|pólskt (pl)||Q7186||Maria Skłodowska-Curie||polsko-francuska uczona, fizyk, noblistka||Maria Curie-Skłodowska; Marie Curie; Maria Skłodowska||Maria Skłodowska-Curie|
Editing an item page
All four fields, the label, description, aliases, and sitelinks, are editable. To edit an existing element, click on the "edit" button and then enter the new or updated information. Then click "save". If an alias or sitelink is incorrect, you can remove it. To do this, first click on the "edit" button and then either delete the alias you wish to remove, or click the bin icon for the sitelink you wish to remove. Then click "save". The element will immediately disappear and be removed from the database.
Deleting an item page
Only admins can delete items. Deletions are done via Wikidata:Requests for deletions. Please give a short reason.
Fyri at fáa meiri leiðbeingin, les her:
- Help:Label, which explains what labels are and what rules they follow
- Hjálp:Frágreiðing, sum greiðir frá hvat ið frágreiðingar eru og hvørjar reglar, ið tær fylgja.
- Help:Aliases, which explains what aliases are and what rules they follow
- Help:Statements, which explains what statements are and what rules they follow
- Help:Sitelinks, which explains what sitelinks are and what rules they follow
- Help:Merge, which explains how to merge items (in case interwiki links to Wikipedia articles in different languages but on the same subject exist on more than one Wikidata page)
For additional information and guidance, see:
- Project chat, for discussing all and any aspects of Wikidata
- Wikidata:Glossary, the glossary of terms used in this and other Help pages
- Help:FAQ, frequently asked questions asked and answered by the Wikidata community
- Help:Contents, the Help portal featuring all the documentation available for Wikidata