Wordpress Display Name Stored In Two Places?

I am wanting to work with the wordpress Display name, however I have realized that this seems to be stored in 2 places in the DB:

wp_users > display_name

wp_usermeta > meta_key (with the value of display_name)

If I do:

get_currentuserinfo();
echo $current_user->display_name;

or

get_bloginfo( 'name', 'display' )

These both seem to be pulling from the wp_usermeta.

Questions:

1. Why is display name stored in two locations?
2. Where is the field in wp_users used in WP?
3. Is there a function to referenc开发者_开发知识库e the one stored in wp_users (display and update)?
4. If I am updating the display name, should I be updating BOTH of these fields?

Thanks!

I would look here: Wordpress Change Default Display Name Publicy As for all existing users

And here: http://wordpress.org/support/topic/change-default-display-name-1

Both links describe how to safely override the function.