I have a List of many-to-many items (cascade="all"). I can load, add and remove items from the list just fine. However, when I save the list and look in the database, the column mapped to the index is zero for all of the elements in the List. I've tried doing a session.save() on the listitem immediately after the element is added to the list, but it doesn't change anything. Am I doing something wrong?

Ok, I missed that an extra table had shown up, and the actual index was in that table. But it seems like a waste of space to have the index column in two places, when it's not used in the second place?

To clarify, the index column is in both the table that bridges the collection and the collection elements, and in the table of the data for the collection element.

Say you have
CREATE TABLE list {
list_id NUMERIC(12) NOT NULL
}
CREATE TABLE ad {
ad_id NUMERIC(12) NOT NULL
}
CREATE TABLE list_ads (
list_id NUMERIC(12) NOT NULL,
ad_id NUMERIC(12) NOT NULL,
sort_order INTEGER NULL
);
Then your mapping for your list would look something like this.

<list name="ad" table="list_ads" lazy="true" cascade="none">
<key column="list_id"></key>
<index column="sort_order"/>
<many-to-many class="com.example.Ad" column="ad_id" />
</list>


hope that helps