Merge vs. Persist?

[swang30]

Entity Manager has a semantic difference between Merge and Persist, however, I notice that the base Data dao just has a "save" method. Does that correspond to the Merge, or is there code that intelligently checks with an exist call and persist if the call returns false?

edit: The reason I ask is that it looks like I may have run into a hibernate issue with OneToMany and deleteOrphan=true. On a merge(which is mapped to EntityManager.merge) Hibernate seems to issue an update setting the join column to null first, before deleting it. On a saveOrUpdate, (mapped to EntityManager.persist) Hibernate does the right thing and issue the delete straightaway...

Jeff

[wgorder]

swang,

This usually is an issue with how you have your relationships mapped. But FYI the implementation for save is as follows:

	@Transactional
	public T save(T entity) {

		if (entityInformation.isNew(entity)) {
			em.persist(entity);
			return entity;
		} else {
			return em.merge(entity);
		}
	}