This is, more or less, working as designed. The semantics of transient are precisely that the data is not persisted. The entity returned from entityManager.merge(obj) is, in fact, an entirely new entity that maintains the state of the object passed into merge (state, in this context, being anything that is not part of the persistent … Read more
You need to use Annotation use-site targets since the default for a property declared in the constructor is to target the annotation on the constructor parameter instead of the getter (which will be seen by JavaBeans compliant hosts) when there are multiple options available. Also using a data class might be inappropriate here (see note … Read more
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);
org.springframework.batch.item.database.JpaPagingItemReader creates is own entityManager instance (from org.springframework.batch.item.database.JpaPagingItemReader#doOpen) : entityManager = entityManagerFactory.createEntityManager(jpaPropertyMap); If you are within a transaction, as it seems to be, reader entities are not detached (from org.springframework.batch.item.database.JpaPagingItemReader#doReadPage): if (!transacted) { List<T> queryResult = query.getResultList(); for (T entity : queryResult) { entityManager.detach(entity); results.add(entity); }//end if } else { results.addAll(query.getResultList()); tx.commit(); } For this … Read more
The above accepted answer is not correct and led me off track for many days !! JPA and Hibernate both accept collections in native query using Query. You just need to do String nativeQuery = “Select * from A where name in :names”; //use (:names) for older versions of hibernate Query q = em.createNativeQuery(nativeQuery); q.setParameter(“names”, … Read more
Put the following properties in your persistence.xml: <property name=”eclipselink.logging.level.sql” value=”FINE”/> <property name=”eclipselink.logging.parameters” value=”true”/> The latter is helpful, so that the values of the parameter are shown. An alternative is using log4jdbc or log4jdbc-remix.
UPDATE: The answer below is valid if you need to stay on a Hibernate version < 5.0. Hibernate 5.0 supports persisting JSR-310 date/time types out of the box. I.e. if you are on Hibernate 5.0 or newer, Adam’s answer is the way to go. Everyone else, read on. The root cause for this at none … Read more
We ran into a similar problem and devised several prospective solutions but there doesn’t seem to be an elegant solution for what seems to be a common problem. 1) Prefixes. Data jpa affords several prefixes (find, get, …) for a method name. One possibility is to use different prefixes with different named graphs. This is … Read more
Is there a way to initialize the EntityManager without a persistence unit defined? You should define at least one persistence unit in the persistence.xml deployment descriptor. Can you give all the required properties to create an Entitymanager? The name attribute is required. The other attributes and elements are optional. (JPA specification). So this should be … Read more
TL;DR T findOne(ID id) (name in the old API) / Optional<T> findById(ID id) (name in the new API) relies on EntityManager.find() that performs an entity eager loading. T getOne(ID id) relies on EntityManager.getReference() that performs an entity lazy loading. So to ensure the effective loading of the entity, invoking a method on it is required. … Read more