I have been reading a lot of db normalization.
The question I have concerns mysql and joining and refrencing.

I realize that you can join a table to allow refrencing in other tables however I have just been reading through the devshed articals on normalization.

www.devshed.com/server_side/mysql/normal/normal2

In this artical they use when creating the table a reference attrib so one column would be

category_id smallint unsigned not null references categories

categories being the other table. From this point forward you can reference anywhere within the multiple tables without any table joins.

I was wondering why this isn't a technique that is shown more often, or if I am interpreting the results incorrectly? This would seem to be a much easier and more efficient way to allow data portability throughout the db layout.