Delete child from parent and parent from child automatically with JPA annotations

Question

Suppose that we have 3 Entities object class:

class Parent {
    String name;
    List children;
}

class Child {
    String name;
    Parent pa         


        

Answer 1

orphanRemoval is delete all orphan entity example: store (s) has books(b1,b2,b3) and b1 has title(t) in this case if deleted store(s) some books(b2,b3) will be deleted. B2 and t still exist. if you use "cascade= CascadeType.Remove" just store(s) and all books will be deleted (only "t" exist).

s->b1,b2,b3 b2->t ------after(orphanRemoval = true)--------- b2->t

s->b1,b2,b3 b2->t ------ after(cascade=CascadeType.REMOVE)--------- t

If orphanRemoval=true is specified the disconnected entity instance is automatically removed. This is useful for cleaning up dependent objects that should not exist without a reference from an owner object.

If only cascade=CascadeType.REMOVE is specified no automatic action is taken since disconnecting a relationship is not a remove operation.