[Deprecated] DMZ 1.6.2 (DataMapper OverZealous Edition)

[eluser]bobosayhello[/eluser]
DMZ looks a nice ORM for CI and I am going to use it. But I have some questions in my mind after some documentation reading.
That is, why does DMZ require the use of an extra joining table even when there is just a one-to-many relationship between two tables? What's the problem with the traditional approach of having a foreign key in the table of 'many' and making it refer to the primary key in the table of 'one'?

We can hardly avoid having an extra joining table for an M:N relationship between two tables. But of course it can be avoided for a 1:N relationship. I believe there has to be some reasons behind this design in DMZ and I would love to know more about it. By the way, I would also like to know if this design affects database performance much.

Any thoughts on this are very welcome.