Question

I’ve been working on an Entity, oneToMany relationship, the problem is that whenever I use this:

//Parent class    

@OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.EAGER, 
        targetEntity = FeedbackCategory.class, mappedBy = "parent")    
@PrivateOwned
@OrderBy("category ASC")
private List<Child> children;

//... other code here, i.e. getters-setters

@PrePersist
@PreUpdate
void prePersistUpdate() {

  // set the foreign key of child to this.ID
  if(children != null && !children.isEmpty())
  {
      for(Child ch: children)
      {
          ch.setParent(this);       
      }          
  }
}

when updating the Parent.class, especially when clean updating the entity, the Id of Parent weren’t being persisted together with the child entity(as foreign key). help please…

it seems that @PreUpdate is not working, @PrePersist totally works.

Answer 1

In general it would be better to correctly maintain your model.

Add an addChild() method that adds the child and sets the parent. Then you model will not be corrupt.

@PreUpdate occurs later in the commit process (after it has determined it needs to update the object). I don’t think there is an earlier JPA event, but you can use the EclipseLink PreWrite event. You will need to use a DescriptorEventListener for this, which can be configured the same way an an EntityListener.