[Mediawiki-l] Database error when deleting a category

[Wang Jerry]

I created a category(Category:HowTo) in my mediawiki and had one page
tagged to it. Then I wanna delete the page Category:HowTo when an
error accoured. It said:

A database query syntax error has occurred. This may indicate a bug in
the software. The last attempted database query was:
(SQL query hidden)
from within function "Article::doDeleteArticle". MySQL returned error
"1364: Field 'ar_text' doesn't have a default value (localhost)".

Anyone knows what was wrong? Thanks a lot.