Persistence Query language

Question

hi guys
I am using persistence query language, I'm trying to delete an entry from the database table. So far I tried 2 approaches
public void destroy(DeviceType deviceType)
em.merge(deviceType);
em.remove(deviceType);
public void delete(int pk)
em.createQuery("Delete from DeviceType dt where dt.deviceTypeID = '"+pk+"'");
both of these methods are not working for me.
please help

Answer 1

Hi shim1,
1. If you're executing destroy in an extended persistence context, em.merge(deviceType) is not needed. In a transaction scoped persistence context, you must change destroy to:
public void destroy(DeviceType deviceType)
DeviceType mergedType = em.merge(deviceType);
em.remove(mergedType);
Please see chapter 3.2.4.1 of the JPA specification for more information about the merge operation.
2. Please change the delete method to:
public void delete(int pk)
em.createQuery("Delete from DeviceType dt where dt.deviceTypeID = ?1").setParameter(1, new Integer(pk)).executeUpdate();
}