when a new message arrive is created in message database msqnnn.db and
in recipient database a pointer is created.

How decide to delete message from message database and when?
It think POA when message message was deleted from all databases user.
When a message is deleted from user database message database is
updated- Is correct?
What's happen when a message was deleted?
Can be recover?
Is a possibility to find what messages was deleted - for a mailbox...