Joins some documents


I read two tamino docu from 4.1.4 and 4.2.1.
And I realized that in docu 4.2.1 “Composition by object reference” is no more included. Why ?

I think “Composition by object reference” is a nice feature in Tamino.
So the developer doesn’t need to care about joins, Tamino joins the documents automatic in Schema layer.

I know there is a problem with XQuery and X-Query.
Is the problem already solved ?
Is using “Composition by object reference” recommeded ?