Error execution delete operation without identification_variable

[bvfalcon]

By executing DELETE FROM entity_name Eclipselink 3.0.3 gives a NullPointerException error. But execution DELETE FROM entity_name x works correctly.

Identification variable is required, but specification defines it as optional.

See demonstration project for details.

Environment:

• Eclipselink 3.0.3
• Derby database driver 10.15
• Java 11

[Tomas-Kraus]

Added simple jUnit into development branch:

    @Test
    public void testDeleteEntityWithoutAlias() {
        final String jpql = "DELETE FROM SimpleEntity";
        final EntityManager em = emf.createEntityManager();
        try {
            em.getTransaction().begin();
            Query q = em.createQuery(jpql);
            q.executeUpdate();
            em.getTransaction().commit();
        } finally {
            if (em.getTransaction().isActive()) {
                em.getTransaction().rollback();
            }
            em.close();
        }
    }

And this test passed:

[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.012 s - in org.eclipse.persistence.jpa.test.jpql.TestBasicJPQL

So looks like future 4.0 is OK.
Will try 3.x branch now.

[bvfalcon]

Yes, you are right, JUnit-test works correctly. My initial description was incorrect
I did found an error. Compare 3 cases in Table:

N	Command	Result
1	DELETE FROM SimpleEntity	correct
2	DELETE FROM org.eclipse.persistence.jpa.test.jpql.model.SimpleEntity	error
3	DELETE FROM org.eclipse.persistence.jpa.test.jpql.model.SimpleEntity o	correct

Case 1 fully corresponds to specification, but cases 2-3 - not. For this reason is strange, that in case 2 we have an error, but in case 3 we have correct result.

[Tomas-Kraus]

OK, I was able to reproduce this. Modified PR #1729 to contain fix and tests for both FQN cases. We need them covered for the future.

[dazey3]

Are we sure the JPA Specification intended to allow for:

    Query query = em.createQuery("DELETE FROM Employee WHERE firstName = :fName AND lastName = :lName");
    query.setParameter("fName", "Peter");
    query.setParameter("lName", "Parker");
    query.executeUpdate();

The examples provided in the specification don't specifically include one where no identification variable is supplied and this query syntax looks more like a NativeQuery than a JPQL one... I know that isn't necessarily concrete evidence, but this query just looks incorrect to me.

I wonder if the JPA Specification is incorrect, or rather not verbose enough to describe the real intention; something like:

    delete_statement ::= simple_delete_clause | where_delete_clause where_clause
    simple_delete_clause := DELETE FROM entity_name [[AS] identification_variable]
    where_delete_clause := DELETE FROM entity_name [AS] identification_variable

IOW: if you don' supply a where_clause, you don't need to provide an identification_variable; we can figure it out for you. But if you do have a WHERE clause, you need identification_variables.

I don't know. What is the usecase of supporting two different syntax in JPQL that do the same thing and are negligibly different? Why support both:

    em.createQuery("DELETE FROM Employee WHERE firstName = :fName AND lastName = :lName");

and

    em.createQuery("DELETE FROM Employee e WHERE e.firstName = :fName AND e.lastName = :lName");