ruby-on-rails – 为什么我的rake db：migrate会抛出错误消息？

当我运行“rake db：migrate”时,我收到以下错误消息：

rake/rdoctask is deprecated.  Use rdoc/task instead (in RDoc 2.4.2+)
rake aborted!
Access denied for user 'root'@'localhost' (using password: NO)

Tasks: TOP => db:migrate
(See full trace by running task with --trace)

是什么原因？