Question

@Entity
public class Parent {
    @Id
    @GeneratedValue(strategy=GenerationType.TABLE)
    int id;

    @OneToMany(cascade=CascadeType.REMOVE)
    List<Item> children = new ArrayList<Child>();
}

@Entity
public class Child {
    @Id
    @GeneratedValue(strategy=GenerationType.TABLE)
    int id;
}

As you can see above, I have a OneToMany-Relation between parent and child. If I delete an instance of parent, all children are also deleted. Is there a way to get this working the other way round as well?

Parent p = new Parent();
Child c = new Child();
p.children.add(c);

EntityManager.persist(p);
EntityManager.persist(c);

EntityManager.remove (c);

This code runs without exception, but when I load p the next time, there is a new child attached.

Answer 1

If you want deletes to work from both sides, you need to define a bi-directional relationship between Parent and Child:

// in Parent
@OneToMany(cascade=CascadeType.REMOVE, mappedBy="parent")
List<Item> children = new ArrayList<Child>();

// in Child
@ManyToOne
Parent parent;