[Zope] referential integrity

[Lukas Maag]

hi zopistas,
Is there a way in zope to define restrictions as we now it from relational databases.


In other words, is it possible to store only a reference of an object in a attribute
of another object. Additionally, the zope database wouldn't allow to delete
the referenced object while it's still referenced (in a attribute of another
object).

if this is somehow possible, it would make zope very, very powerfull.

thanx, lukas