Anamespace is a collection of pages all having a similar purpose. Namespaces can be thought of as partitioning the information within a wiki into different types, keeping "real" content (pages about the main subject matter of the wiki) separate fromuser profiles,help pages, etc.A namespaceprefix is the first part of a page title (if present) indicating which namespace it belongs to. It is separated from the rest of the title by a colon (:). The so-called "main namespace" does not have a prefix.Every namespace has anumber orindex which the MediaWiki software uses to refer to the namespace instead of its name.
Every page on a wiki has a unique title which may begin with a namespace prefix or not. Pages in different namespaces can otherwise share the same name (i.e., not counting their prefixes).
For example, here at MediaWiki.org:
| Title | Namespace prefix | Namespace number | Page description |
|---|---|---|---|
API | 0 | a page in the "main namespace" | |
Template:API | Template | 10 | atemplate that can be transcluded into other pages |
Manual:API | Manual | 100 | a page in ourMediaWiki manual (which, in this case, redirects to a different page) |
Because the "main namespace" does not have a prefix, any page title having no prefix—or any page whose apparent prefix doesn't match any recognized namespace on the wiki (nor anyinterwiki/interlanguage prefix)—is interpreted as a page in the main namespace.
Note that pages in the main namespace cannot have names starting with any existing namespace prefix followed by a colon, because such pages would be rendered inaccessible by the presence of that namespace.(If this has happened as the result of the creation of a new namespace, thenamespaceDupes.php maintenance script can be used to fix the problem.)
Pages can bemoved between namespaces simply by changing the prefix part of their title.
Namespace prefixes can be translated, and aliases (helpful in shortcuts) can be configured for each (see$wgNamespaceAliases).All namespaces also have a "canonical" prefix, which works on all wikis regardless of configuration.Aliases and canonical names can be used in links, when performing asearch, and in the page title with the help of the {{DISPLAYTITLE}}magic word.
Each namespace has a correspondingnamespace index. Within the database, the title is split into namespace index and text title, and this is used for storage in thepage.page_namespace andpage.page_title columns, among others.
Most namespaces have an associateddiscussion namespace (or "talk" namespace).All discussion namespaces have odd-integer indices, and the discussion namespace index for a specific namespace with indexn isn+1.The namespaces with even-integer indices aresubject namespaces (note that this is a distinct concept fromcontent namespaces).The subject-talk duality can be explored using the{{SUBJECTPAGENAME}} and{{TALKPAGENAME}}magic words.The<body> tag of pages in talk namespaces has thens-talk CSS class, which might be useful for styling.
MediaWiki ships with 18 built-in namespaces:
The full list is presented in the table below.
| ID | Name | Purpose | Talk | |
|---|---|---|---|---|
| 0 | (Main) | "Real" content articles[1] | Talk | 1 |
| 2 | User | User pages[2] | User talk | 3 |
| 4 | Project | Information about the wiki[3] | Project talk | 5 |
| 6 | File | Media description pages | File talk | 7 |
| 8 | MediaWiki | Site interface customization[4] | MediaWiki talk | 9 |
| 10 | Template | Template pages | Template talk | 11 |
| 12 | Help | Help pages | Help talk | 13 |
| 14 | Category | Category description pages | Category talk | 15 |
| -1 | Special | Holds special pages | N/A | |
| -2 | Media | Alias for direct links to media files | ||
Each namespace also has a constant derived from its name, with all letters in uppercase, spaces replaced by underscores, and prefixed byNS_.For example, the constant for the "User talk" namespace isNS_USER_TALK.A complete list can be found inExtension default namespaces.
$wgMetaNamespace, which unless manually set otherwise, defaults to$wgSitename.Extensions and site administrators can define additional namespaces to group additional classes of pages together.For a thorough overview, seeManual:Using custom namespaces.
Some namespaces, like Project and Help, only exist for convenience and do not have any extra functionality compared to the Main namespace.
Template namespace pages can betranscluded without namespace prefix.
User namespace pages are associated with user accounts or IP addresses. Changes touser talk pages generate an automatic message notification.
Pages in the"MediaWiki" namespace are used to override default messages inlanguage file and can only be edited by administrators or other users with theeditinterface permission.
File and Category pages have special functionality, as described inHelp:Managing files andHelp:Categories.Files can be moved by users with the "movefile" right.Category pages can be moved by users with the "move-categorypages" right.
All pages in discussion namespaces have a "post a comment" feature.