Tables: Notification_Alert & Notification_Alert_Recipient - UserID used in both the tables
Both these tables have a field User_ID (which probably indicates the recipient). Why is there a User_ID in the Notification_Alert table? (there is another field Creator which indicates the creator of the alert ) We already have a Notification_Alert_Recipient table which maps an alert to a recipient.
So, as per the discussions with Ben,
Drop the field 'user_id' from the Notification_Alert table.
Corresponding changes need to be made to the Data_Model document.