Jpa Criteria Table alias

Question

Hi i'm struggling to write the following query with criteria api: "SELECT c.id,curr.name FROM Cargo c, Currency curr"

The problem is that both Cargo and Currency are aliased as c by criteria so the resulting jpql becomes "SELECT c.id,c.name FROM Cargo c, Currency c".

I don't know if it is because both entities start with C. Is there a way to chage the table alias?

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Tuple> query= criteriaBuilder.createTupleQuery();

Root<Cargo> cargo= query.from(Cargo.class);
Root<Currency> currency= query.from(Currency.class);

Any help is very much appreciated.

Answer 1

Your code is missing the part where you specify what you want selected. "SELECT c.id,curr.name FROM Cargo c, Currency curr" would likely translate to something like:

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Tuple> query= criteriaBuilder.createTupleQuery();

Root<Cargo> cargo= query.from(Cargo.class);
Root<Currency> currency= query.from(Currency.class);

query.multiselect(cargo.get("id"), currency.get("name"));
Query query = em.createQuery(cq);
List<Tuple> results = query.getResultList();

There is an example here using only one table: http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Basic_JPA_Development/Querying/Criteria#Tuple_Queries

Answer 2

After lots of debugging, i found out that the actual jpql that is executed is different from the one that is displayed in my ide(eclipse). The aliases were ok.I think i was a bit deceived by the ide. Thanks all for your attention.