I have a database ,it's locale is "zh_tw.big5". I want to change the database locale,so I try to update the "systables" on my database set the column "site" to equal "th_th.thai620". And I assign the DB_LOCALE,CLIENT_LOCALE to "th_th.thai620". But it can't work,I can't connect my database and I can't delete my database. What is correct procedure to change the database locale and how to fix my database??