eclipselink

It's possible to define enumerations in JPA using either @Enumerated(EnumType.ORDINAL) or @Enumerated(EnumType.STRING) I wonder what are advantages and disadvantages of those two definitions? I heard that ORDINAL performs better (is faster) than STRING with EclipseLink. Is that true? I always go STRING . Speed is rarely the most important issue - readability and maintainability are more important. I use STRING because it's a lot easier to manually inspect rows from the database, but more importantly, I can do two things, without touching the database, the ORDINAL can't handle: I can change the

I would like to know how to implement temporal tables in JPA 2 with EclipseLink. By temporal I mean tables who define validity period. One problem that I'm facing is that referencing tables can no longer have foreign keys constraints to the referenced tables (temporal tables) because of the nature of the referenced tables which now their primary keys include the validity period. How would I map the relationships of my entities? Would that mean that my entities can no longer have a relationship to those valid-time entities? Should the responsability to initialize those relationships now do by

Why doesn't it work: @Test public void test() { EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("test-pu"); EntityManager entityManager = entityManagerFactory.createEntityManager(); String id = "id"; long value = 1234L; entityManager.getTransaction().begin(); FancyEntity fancyEntity = new FancyEntity(id); entityManager.persist(fancyEntity); int updateCount = entityManager.createQuery("update FancyEntity item set item.value = ?2 where item.id = ?1").setParameter(1, id).setParameter(2, value).executeUpdate(); assertEquals(1, updateCount); FancyEntity