On Sun, Jun 13, 2010 at 5:55 AM, 杨杰 <xtyangjie(a)gmail.com> wrote: You can use API [1] function "prop=categories" to query any pages. Or you could obtain a database dump [2] and query the `categorylinks` table. 1. http://en.wikipedia.org/w/api.php 2. http://dumps.wikimedia.org/backup-index.html They are stored in MySQL, see [3] and [4]. 3. http://www.mediawiki.org/wiki/Manual:Category_table 4. http://www.mediawiki.org/wiki/Manual:Categorylinks_table I'm in Xi'an too :P -- Jimmy Xu

杨杰 wrote: Categories are edited by normal users, just like articles. Sometimes a category is missing, and then it is created, often following a pattern of other categories. For example if there are categories for French food and German food, I might create a category for Swedish food. Sometimes a user analyses a bigger part of the category structure and proposes that food categories should be named by ethnic origin rather than country, or that food and drink should be one category instead of separate categories. But the user who does this for food and drink is not the same user that does this for pet animals or vintage cars. And on another language of Wikipedia, the category structure could be completely different. Many languages have a page for discussions about the category structure, such as http://en.wikipedia.org/wiki/Wikipedia:Categories_for_discussion So far, this is not a "technical" issue that is discussed on wikitech-l. The technical part is just making sure that the creation and editing of categories can be done. This also involves some semi-automatic tools such as using a "bot" to move articles from one category to another. -- Lars Aronsson (lars(a)aronsson.se) Aronsson Datateknik - http://aronsson.se