mapping a composite foreign key in a query

Question

Hibernate cannot seem to find the composite foreign key conceptPk in my JPA query. How can I get hibernate to recognize the composite foreign key?

The following JPA:

@SuppressWarnings("unchecked")
public Collection<SnomedDescription> findDescriptionForConcept(SnomedConcept conc) {
    Query query = this.em.createQuery("SELECT descr FROM SnomedDescription descr WHERE descr.concept =:cid");
    query.setParameter("cid", conc);
    return query.getResultList();
}

Is generating the following hibernate SQL, which shows that hibernate is not recognizing the embedded key:

select snomeddesc0_.effectiveTime as effectiv1_60_,
 snomeddesc0_.id as id2_60_,
 snomeddesc0_.active as active3_60_,
 snomeddesc0_.inSnapshot as inSnapsh4_60_,
 snomeddesc0_.languageCode as language5_60_,
 snomeddesc0_.moduleId as moduleId6_60_,
 snomeddesc0_.Term as Term7_60_
 from sct2_description snomeddesc0_
 where (snomeddesc0_.effectiveTime, snomeddesc0_.id)=(?, ?)

As you can see, hibernate is trying to map descriptionPK in the where clause, when it should be mapping description.concept.conceptPk in the where clause. How can I fix this?

Answer 1

Make sure you have appropriate equals/hashcode methods implemented in all entities especially Concept and ConceptKey to fix the issue you having.

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result
            + ((conceptPk == null) ? 0 : conceptPk.hashCode());
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }
    Concept other = (Concept) obj;
    if (conceptPk == null) {
        if (other.conceptPk != null) {
            return false;
        }
    } else if (!conceptPk.equals(other.conceptPk)) {
        return false;
    }
    return true;
}