actually, i had the same problem as them above, aand change the default prefix (wp_) manually (one by one) is not a good job, why? ..because i’ve a bunch plugins which has been installed on my own blog, and of course it using wp_ prefix too, one of these are firestat.
but, i am successfully changing the default prefix (wp_) using my own method, see below:
1. backup your wordpress database (i’m using phpmyadmin) to an *.sql file.
2. open that *.sql file (make another copy first) using text editor, then find and replace all “wp_” prefix to “something_”.
3. now, drop all tables of your wordpress databases (don’t drop the database )
4. import the *.sql file which has been edited before into your wordpress databases.
5. and lastly, edit your
wp-config.php file and change the $table_prefix = ‘wp_’; to $table_prefix = ’something_’;
6. in my case, all plugins will be deactivaed automatically, so login to your blog admin panel, then activated your all plugin.
7. done !
it work perfectly for me.. !
这种方法比那种在phpmyadmin上改表前缀的方法要快得多，一步就全部修改完毕（这样看mysql比SQL server和access方便多了啊），不需要再像下面的文章《如何修改Wordpress表前缀》多步修改wp_这个前缀了。而且已安装的插件也不会出问题了。
------------------------------------------
如何修改Wordpress的表前缀
WordPress的表名前缀默认为 wp_，该值为Wordpress安装时指定，安装之后无法更改。但若不得已需要改变时，可以使用以下方法。
- 将数据库导出。
- 将表中的所有
wp_替换为wp2_，其中 wp2_` 为新的表前缀。 - 导入数据库。
- 修改
wp2_options表的数据，在第四行左右有个wp_user_roles，将其修改为wp2_user_roles。 - 修改
wp2_usermeta表的数据，将所有的wp_user_level修改为wp2_user_level，所有的wp_capabilities修改为wp2_capabilities。
如果忘记修改
wp2_options 和 wp2_usermeta 中的值，后台管理就无法使用。