I am trying to find out a way to easy manage a children collection within a parent object by adding, removing or changing the entries in a collection a children object referenced by a parent object.
Is there a way to make these changes to the children Set persistent?
My case is a one to many parent child relationship, with inverse= true and the the constraint in the foreign key column of the child table forced to be not null.
The only way it seems to work is to remove a child object from the children Set and deleting it from he database, like this:

parent.geTheCildrenSet().remove(child);
session.delete(child);

I would like somehing like:

parent.getTheChildrenSet.remove(aChild);
parent.getTheChildrenSet.add(new Child());
...
...
session.saveOrUpdate(parent);

Is this possible one way or another?

Many thanks.

You need a cascade="all-delete-orphan" on the collection mapping. Refer to the Hibernate documentation or the book for more information.
Basically this means any saves/updates to the parent will be cascaded to the children as well as removal of any object from the parent collection will delete the child row that was just removed.

It looks like it is working now.

Here are the data related to the two classes:

Parent:
........................
<set name="RuleContextKws" inverse="true" cascade="all-delete-orphan" lazy="false">
<key column="rule_id"/>
<one-to-many class="RuleContextKw" />
</set>
.........................

Child: (the child has a composite key but this should not be relevant)
....................................
<composite-id name="Id" class="RuleContextKWPK">
<key-many-to-one
name="RuleId"
column="rule_id"
class="Rule"
/>
<key-property
name="Keyword"
column="keyword"
type="string"
length="50"
/>
</composite-id>
......................................

The code just creates a session when loading the parent object from the DB and then it closes it. By having now the reference of the whole object the client just plays around with the Set of children adding and/or removing entries in the collection.
Eventually a new session is open along with a new transaction and the update (or save) parent method is invoked.




About the database I don't know if it is related but verything started to work when I added the cascade constraint on the foreign key to the parent table.
I hope this can help even the others who are struggling with this kind of issues.