Wiki Category Links

When a page with a redirector is changed the Categories on that page disappear. To correct this problem some SQL is needed. This page gives background information on pages links and categories.
At the SQL Category tab a SQL summary containing a solution.

Involved tables and structure

Table CategoryLinks

CategoryLinks
Field	Type	Attrib	Description	Example
cl_from	int(8)	Unsigned	Id equal to the pageId	1583
cl_to	varchar(255)	Binary	CategoryName to link to	Private
cl_sortkey	varchar(86)	Binary	CategoryName to sort-on	Index
cl_timestamp	TimeStamp(14)	Timestamp	Time/date stamp	20060603125034

Meaning: The page 1583 (= Index) links to the Category Private. On the Private page use Index as sort-key.

Table Page

Page (Not full structure given)
Field	Type	Attrib	Description	Example
page_id	int(8)	Unsigned	Unique Page Id	1583
page_namespace	int(11)		Namespace	14
page_title	varchar(255)	Binary	Name of the page	Index

Meaning: The page 1583 (= Index) belongs to the namespace 14 (= Categories).

Table PageLinks

PageLinks (Not full structure given)
Field	Type	Attrib	Description	Example
pl_from	int(8)	Unique	Id equal to PageId	1583	1583
pl_namespace	int(11)		Number of the Namespace	10	14
pl_title	varchar(256)	Binary	Name of the page	CatAZ	Index

Meaning: Page 1583 (= Index) has namespace 10 (= Template) CatAZ, Page 1583 (= Index) has namespace 14 (= Categories) Index.

Mediawiki Namespaces

Variables	Alternate syntax	Name, linked to list of all pages	Notes
{{ns:-2}}	{{ns:Media}}	"Media"	pseudo-namespace for images and other files
{{ns:-1}}	{{ns:Special}}	"Special"	pseudo-namespace for special pages (list: Special:Specialpages)
{{ns:-0}}	{{ns:Main}}	main	main namespace, no prefix,
{{ns:1}}	{{ns:Talk}}	Talk	see Help:Talk page for this and the following odd-numbered namespaces
{{ns:2}}	{{ns:User}}	User	logged-in users (list: Special:Listusers)
{{ns:3}}	{{ns:User_talk}}	User talk
{{ns:4}}	{{ns:Project}}	HaFrWiki42	the project namespace for matters about the project
{{ns:5}}	{{ns:Project_talk}}	HaFrWiki42 talk
{{ns:6}}	{{ns:Image}}	File	images and other uploaded filespage]]s (list: Special:Imagelist)
{{ns:7}}	{{ns:Image_talk}}	File talk
{{ns:8}}	{{ns:MediaWiki}}	MediaWiki	system messages (list: Special:Allmessages)
{{ns:9}}	{{ns:MediaWiki_talk}}	MediaWiki talk
{{ns:10}}	{{ns:Template}}	Template	the default namespace for templates:
{{ns:11}}	{{ns:Template_talk}}	Template talk
{{ns:12}}	{{ns:Help}}	Help	typically used for the MediaWiki User's Guide,
{{ns:13}}	{{ns:Help_talk}}	Help talk
{{ns:14}}	{{ns:Category}}	Category	each page (list: Special:Categories) represents a category of pages,
{{ns:15}}	{{ns:Category_talk}}	Category talk

• Namespace

SQL Category

To find the page number of the Article.

SELECT  * 
FROM    page
WHERE   page_title =  'You''re_beautiful';

This will give:

page_id    page_namespace  page_title        Etc.
XXXX                    0  You're_beautiful  Etc.

Now insert 2 record into the CategoryLinks table.

cl_from    cl_to     cl_sortkey           cl_timestamp
   XXXX    Index     You're beautiful     20060708223318
   XXXX    Music     You're beautiful     20060708223409

NB: Important the Category page is cached. To see the result, first clear the cache and refresh the Category page.