Hi all, sorry my bad english...
I need to delete a parent, but keep yours childs.
My problems is: I have an group, such as "programers'" and yours users "john", "mary" and "george".
I need to delete the "programers" group, but preserve the users "john", "mary" and "george" (because these users are used in other groups).
The relation between groups an users is N-N where exists cascade="save-update" in group way. This mechanisms throw constraints exceptions in DB when I try to delete a group "programers".

PS. I'm using 3tier architecture where the parent (group) is returned to UI without childs (users) - lazy="true".

at the beginning of this chapter:http://www.hibernate.org/hib_docs/reference/en/html/example-parentchild.html

All right, I found the solution, but my DBA did not like the solution (...)
Having in mind that (1) for each parent I need to load all collections of children and, for each collection item I need to make one update and (2) if this parent was child in others collections, I need to load all collections where the parent is child and, for each item of these collections I need to make one another update (...) It is a beautiful shit!

So, I cannot simply make an delete by native SQL in n-n resolution tables?