Re: a union is always a join!

PS to answer your question:

>Is there a database theory that can establish a good database design
>which will not allow screwing up of history and which uses insert,
>delete and update operations?

I don't think you can do anything about data being wrong. But there is literature on "historical" and "temporal" databases, e.g.

  http://archive.nyu.edu/handle/2451/14609

seems to be roughly where you're heading.

-- 
Reinier