I am starting to implement an MTI solution and have a basic question. I have 3 physical models - SMSNotifications, EmailNotifications, TwitterNotifications and they are subclasses of notification. At times in my code, I want to say Notifications.find(:all)so that I can get a set of results sorted by their creation time. Then I want to do things based on their subclass. What is the way to write Notifications.find(:all) and have Rails look through the subclass tables and combine the results? Right now Rails still thinks I have a physical Notifications table which goes against my MTI design.

I am also considering the possibility that I should be using STI instead. I would probably have 10 empty columns per row but if getting all notifications requires a query for each type of notification, then I feel like this could be a big issue.

Thanks!