Re: [development] Can I use an external user DB instead of the original user table in drupal DB?

I want users to provide more profile, and module profile can solve this issue. But it's not convenient to query the data, which user provides. Because the data has been saved in 'profile_fields' and 'profile_values', two tables separately.

Think you're missing the point of "API". Use the user_load() function which loads a user, profile and all for your convience. If you want to see the structure returned (and where the profile fileds are) install the devel module which can display this for you. http://api.drupal.org/api/5/function/user_load