Question

I run a JPA 2.0 native query like this:

Query query = em.createNativeQuery("SELECT NAME, SURNAME, AGE FROM PERSON");
List list = query.getResultList();

now list has all the rows returned by the query. I can iterate over them, but every entry is an Object[] where:

• at index 0 I find NAME
• at index 1 I find SURNAME
• at index 3 I find AGE

Did anyone find a way to do something like this:

Map<String, Object> row = list.get(index);
String name = row.get("NAME");
String surname = row.get("SURNAME");
Integer age = row.get("AGE");

I would need this since the native query that I execute is a dynamic one and I don’t know the order of the field in SELECT clause, so I don’t know id the query will look like:

SELECT SURNAME, NAME, AGE FROM PERSON

or

SELECT AGE, NAME, SURNAME FROM PERSON

or even

SELECT AGE, SURNAME, NAME FROM PERSON

Answer 1

Which JPA are you using – Hibernate, EclipseLink or something else?

There is no standard way to do this in JPA but your specific implementation may allow it – for example, Eclipselink has a query result type hint.

http://dev.eclipse.org/mhonarc/lists/eclipselink-users/msg03013.html

Query query = entityManager.createNativeQuery(sql);
query.setHint(QueryHints.RESULT_TYPE, ResultType.Map);

For Hibernate, with javax.persistence.Query dbQuery:

org.hibernate.Query hibernateQuery =((org.hibernate.jpa.HibernateQuery)dbQuery)
.getHibernateQuery();
hibernateQuery.setResultTransformer(AliasToEntityMapResultTransformer.INSTANCE);