in reply to ORM with version control?

I've made tables that have id, version as the primary key, plus a "current" field. Then I have a view that only selects the "current" items, and use whichever is appropriate. Something like this-
create table all_properties ( id int primary key; // Same across all different versions! vers int primary key; current boolean; created_by char(40); created_on date; property_name, property_value, etc.... ) create view current_properties as select * from all_properties where current=boolean;
Then you don't get the storage hit and headaches that materialized views can give you, and it's rather clean conceptually.

You probably still want a trigger to be sure "current" is only true for one version.

(I cheat a bit by letting "vers" be null for the current version, and not having a "current" field, which works OK only if you want the most recent version to always be the default one- which isn't your situation.)