I think I really have problems in understanding the usage of unsaved-value.

class X ...
id .... unsaved-value = "any/none/null.."
generator = "assigned"

class Y
id ... unsaved-value = "null"
generator = "sequence"

many-to-one = x cascade= "save-update"


I really have doubts to solve the unsaved-value problem for the assigned id.

if I used the generator = " sequence" for X id, and define unsaved-value="null", it works correct since it calls save when id is null or else update if the id is not null.
but for generator = " assigned", what should I set the unsaved value to force hibernate to act as :

saveOrUpdate(y) :

saving y..
saving or updating x? // many-to-one cascade
if x is in the session(db), update x
else save it
x saved or updated
y saved

unsaved-value does not work properly for assigned ids. This problem is described in the Hibernate 2.1 documentation, along with the solution using Interceptor.isUnsaved().

In Hibernate3, you don't have to specify unsaved-value, and everything Just Works.

if I dont specify unsaved value for the ids, it gives

"a different object with the same identifier was already associated with the session...."