I was looking through the different databases seeing how the usernames were listed in each database (vmail, roundcubemail, sogo). I noticed each of these databases has a table with users.
vmail= "mailbox" table > username
sogo= "users" table
roundcubemail= "users" table

Two questions:

1) Are these user tables all linked? I know if I create a new user in iredadmin panel it adds an entry in all three places. But if I delete directly from one db will it delete all the others?

2) I wanted to configure SOGo to not use the full email address to login, but since the username is entered as "user@domain.com" in the sogo user db I cannot do this. I only use one domain, so when creating users, can they get created as "username" instead of username@domain.com?
If not, will using LDAP instead of MySQL during setup make this be possible?

Thanks

==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.5.1
- Linux/BSD distribution name and version: Ubuntu 14.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Apache
- Manage mail accounts with iRedAdmin-Pro?
- Related log if you're reporting an issue:
====