Insert called before delete in a collection with unique constraint

Question

Hi all,
I have a simple @OneToMany private mapping:
private Collection<Item> items;
@OneToMany(mappedBy = "parent", cascade = CascadeType.ALL)
public Collection<Item> getItems() {
return items;
public void setItems(Collection<Item> items) {
this.items = items;
public void customize(ClassDescriptor classDescriptor) throws Exception {
OneToManyMapping mapping = (OneToManyMapping)
classDescriptor.getMappingForAttributeName("items");
mapping.privateOwnedRelationship();
I have a unique constraint on my Items table that a certain value cannot be duplicated.
My problem appears when I remove a previously saved item from the collection and add a new item containing the same data, at the same time.
After I save the parent and do a flush, I receive SQLIntegrityConstraintViolationException because TopLink performs first an insert query instead of deleting the existing item.
I tested the application and everything went fine with: remove item / save parent / insert item / save parent
I checked on the Internet and the documentation but didn't find anything similar to my problem. I tried debugging TopLink's internal calls but I'm missing some general ideas about all the inner workings and don't know what to look for. I use TopLink version: Oracle TopLink Essentials - 2.1 (Build b60e-fcs (12/23/2008))
Does anyone have a hint of what to look for?
Edited by: wise_guybg on Sep 25, 2009 4:01 PM
Edited by: wise_guybg on Oct 5, 2009 11:22 AM

Answer 1

Thank you for the suggestions James
As I mentioned briefly I have done some debugging but couldn't understand how collections are updated. What I did find out is that setShouldPerformDeletesFirst() doesn't come into play in this case because this is not a consecutive change on entities.
What I have in my case is a collection inside an entity that the user has tampered with and now TopLink has to do a merge. I cannot call flush() in the middle since the user has not approved that the changes made to the entity should be saved.
I see that for TopLink it's not easy to figure out the order in which changes were made to a collection. Here is pseudo-code of when the constraint is touched:
entity.items.remove(a)
entity.items.add(b)
merge(entity)
And here is code that executes without a problem:
entity.items.remove(a)
merge(entity)
entity.items.add(b)
merge(entity)
So once again, I think that collection changes are managed differently but I don't find a way to tell TopLink how to handle them. Any ideas?