Hibernate's Transformers.aliasToBean() method

Question

 Query query =  getHibernateTemplate().getSessionFactory().getCurrentSession().createSQLQuery(
                 "select proj_employee.employee_no as employeeNo, ...
 .setResultTransformer(Transformers.aliasToBean(User.class));

Inside User.class does the property employeNo need to be in capital letter?

private String EMPLOYEENO; 
//get/set for EMPLOYEENO

If I change the EMPLOYEENO to small letter, it doesn't work. Can anyone explain why the variable name must be all capital letters?

Answer 1

See the Hibernate 3.2: Transformers for HQL and SQL blog post:

SQL Transformers

With native sql returning non-entity beans or Map's is often more useful instead of basic Object[]. With result transformers that is now possible.

List resultWithAliasedBean = s.createSQLQuery(
  "SELECT st.name as studentName, co.description as courseDescription " +
  "FROM Enrolment e " +
  "INNER JOIN Student st on e.studentId=st.studentId " +
  "INNER JOIN Course co on e.courseCode=co.courseCode")
  .addScalar("studentName")
  .addScalar("courseDescription")
  .setResultTransformer( Transformers.aliasToBean(StudentDTO.class))
  .list();

StudentDTO dto =(StudentDTO) resultWithAliasedBean.get(0);

Tip: the addScalar() calls were required on HSQLDB to make it match a property name since it returns column names in all uppercase (e.g. "STUDENTNAME"). This could also be solved with a custom transformer that search the property names instead of using exact match - maybe we should provide a fuzzyAliasToBean() method ;)

Maybe you are facing the same situation than the one described in the tip in which case you should try to add calls to addScalar().

Answer 2

Consider putting column aliases in double quotes. Oracle doesn't uppercase aliases specified in double quotes.

Query query =  getHibernateTemplate().getSessionFactory().getCurrentSession().createSQLQuery(
                 "select proj_employee.employee_no \"employeeNo\", ...
 .setResultTransformer(Transformers.aliasToBean(User.class))

;