Question

Let’s say I have two classes, Parent and Child. These two are related via a uni-directional relationship.

<bag name="children" cascade="all">
    <key column="parent_id" />
    <one-to-many class="Child" />
</bag>

If I want to add a child element to the parent, as far as I know I need to load the parent, add a child to it, and save the parent:

Parent p = dao.getParent();
Child c = new Child();
p.getChildren().add(c);
dao.saveOrUpdate(p);

However, a problem arises when trying to mirror this change in the data model backing the GUI. As far as I can tell, there’s no way of finding the primary key that was assigned to c when it was persisted. This is causing a problem in the GUI, for if I add multiple rows to the model it’s impossible to distinguish them for later use.

Any ideas how I might be able to access the child’s primary key after it’s been persisted?

Answer 1

You can access autogenerated keys after the session is flushed, i.e. either after an explcit session.flush() or after transaction commit.