Hibernate version: 3.1

Due to some excellent help from a forum member I was able to define a class containing a subclass that contains a list of the class:




and hibernate 'likes' this and I can create instances of Activitystep subclasses and their lists and save them into the database just fine.

The problem arises when I have another different class that wants to declare/use a list of Activitystep. My current definition is:



The list is supposed to be a list of steps, that may themselves contain a list of steps, that may also contain ...

At runtime, I get the following error:



Is there a better or proper way to define the Steps list to achieve my goal. Obviously I'm still a relative newbie at Hibernate.

Any help would be appreciated

I believe that your Lists that contain many-to-many relationships must specify the table attribute, to indicate the cross-reference table.

EG,

In your first example showing ActivityStep and ForStep, you could use a table named ForStepParents. This contains 3 columns: parent_id (foreign key to a ForStep), child_id (foreign key to the child ActivitySteps), and listIndex. In this case, the list tag should be:
<list name="Steps" table="ForStepParents" cascade="all,delete-orphan">
<key column="parent_id"/>
<index column="listIndex"/>
<many-to-many class="ActivityStep" column="child_id"/>
</list>

Your second example, with Activites and Steps, would also need a similar table.

The ActivityStep table has multiple subclasses (lots actually) but works fine without specifying a table whe your just creating lots of ActivityStep entities. One index table is created automatically.

I think the problem is that the stepchildID must exist before the Activities list can be stored as there is a constraint based upon that key but the stepchildID gets created as part of the list (or something to that effect). Is this a chicken and egg problem?

As a follow-on to the first message is that Activities sort-of wants to define a list and just refer to another class for the contents. The definition of ActivityStep should not have to be redone. Perhaps I am doing this wrong. Maybe what I want can't be done.

Again, still looking for help adn all is appreciated.