Parent Child relationships

rpunnoose · **Joined:** Wed Jul 09, 2008 1:50 pm **Posts:** 2

[b]Hibernate version:3.2.6.ga[/b]

[b]Hibernate annotations version:3.3.1.GA[/b]

I have an Alert class which has a reference to a Collection of Comment objects. Using annotations "OneToMany" and the cascade=CascadeType.ALL, I can delete an Alert and it will delete the associated Comment objects. However, is there a way to delete the Comment and have it update the Collection of Comment objects of the referenced Alert. Right now it causes a foreign key exception.

Any ideas?

Roshan

carlolf · **Posted:** Wed Jul 09, 2008 3:48 pm

Here is an example which works for me when I do an update call on the owner of the collection (all my objects are detached before update call):

Code:

@OneToMany(mappedBy ="assessment", cascade = {CascadeType.ALL}, fetch=FetchType.EAGER)
  @org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
  private Set<FinancePosition>financePositions = new HashSet<FinancePosition>();

There must be some other problem in your code or mapping, when you get a foreign key exception.

rpunnoose · **Joined:** Wed Jul 09, 2008 1:50 pm **Posts:** 2

I dont believe that works if you try to delete the child itself. Which is what I am having issues with? For example, Parent has multiple Children, then by deleting a child, without reference to the parent, the parent's join table/collection should be updated as well. I feel as if the delete should first remove the child from the Join table and then delete the child itself.

Parent <>--- Child

//with no access to the parent
session.delete(child)

Roshan

carlolf · **Posted:** Thu Jul 10, 2008 2:09 am

In my own stuff I just do remove the child from the parent's collectionand the I call the merge method on the parent.

The following is from the Hibernate Annotations Doc, p.49:

Quote:

DELETE_
ORPHAN applies only to @OneToMany associations, and indicates that the delete()/remove() operation
should be applied to any child object that is removed from the association. In other words, if a child is dereferenced
by a persistent parent and if DELETE_ORPHAN is used, the "orphaned" child is deleted.