复合主键的休眠问题

Question

I am facing some issues with Hibernate. We need to save an object with its children. Each child has a composite primary key. One property of the key will be inserted by a trigger. Another property will be set from the program before calling saveOrUpdate(Object) .

But we are not able to save the object. Hibernate throws the exception Same identifier is already exists in the session .

I have tried session.clear() , but I get the same exception. When I tried session.merge() , only the last child was saved, others were ignored.

Answer 1

If you aren't going to need in the same Hibernate Session the objects once saved, you could detach them right after saving with Session.evict() :

// children is the collection of detached children, ready to save
for (Child child : children){
    session.save(child);
    session.evict(child);
}

Alternatively, this entry in the Hibernate Forums might be helpful: Before Insert Trigger and ID generator . There's an implementation of an AbstractPostInsertGenerator you can integrate to suit your needs.