Hey,
I don't play with JPA too much, but I saw this:
http://www.datanucleus.org/products/datanucleus/jpa/transactions.html
Jake
On Feb 9, 10:55 am, Johan Vallejo <jvall...@vnperu.com> wrote:
> Hi Jake,
> Now i have this error
> Log :javax.persistence.PersistenceException: Transaction is still active. You
> should always close your transactions correctly using commit() or rollback().
> this is my code :
> EntityManager cn2 = emf.get().createEntityManager();
> distritos dist2 = cn2.find(distritos.class, id);
> evento e = new evento();
> e.setDistrito(dist2);
> Date fecha = new Date();
> e.setFechaCreacion(fecha);
> try{
> cn2.getTransaction().begin();
> cn2.persist(e);
> cn2.getTransaction().commit();
> response.getWriter().write("ok");
> }finally{
> cn2.close();
> }
> Distrito :
> @Entity
> public class distritos implements Serializable {
> @Id
> @GeneratedValue(strategy = GenerationType.IDENTITY)
> @Extension (vendorName="datanucleus", key="gae.encoded-pk", value="true")
> Key id;
> --getter and setter--
> El 08/02/2010 03:37 p.m., Jake escribió:Hello, The Google Datastore has four
> ways that you can store a Primary Key ID: String, Long, and two variations on
> Google's own Key object. If you want to create a parent/child relationship
> between two persisted objects (in your case, evento is the parent and
> distritos is the child), then you need to use Google's Key object as the
> primary ID.
> See:http://code.google.com/appengine/docs/java/datastore/creatinggettinganddeletingdata.html#Keys"If
> the class is used as a "child" class in a relationship, the key field must
> be of a type capable of representing an entity group parent: either a Key
> instance, or a Key value encoded as a string." So, you have two options: 1.
> Change your Long id values to Key id values. 2. Instead of storing "private
> distritos distrito" directly in your evento object, store a reference to the
> id: "private Long distrito_id" Jake On Feb 6, 4:06 pm,
> chevelle<jvall...@vnperu.com>wrote:Hi I am new in the list, in these days i
> am trying save data between two entity beans using JPA but without success, i
> am cheking the log nd says: Uncaught exception from servlet
> javax.persistence.PersistenceException: Error in meta-data for
> beans.distritos.id: Cannot have a java.lang.Long primary key and be a child
> object (owning field is beans.evento.distrito). this is my servlet:
> Long id = Long.parseLong(request.getParameter("idDistrito"));
> response.setContentType("text/html"); EntityManager cn =
> emf.get().createEntityManager(); Query q = cn.createQuery("SELECT
> d FROM distritos d WHERE d.id = :codigo");
> q.setParameter("codigo",id); distritos dist = (distritos)
> q.getSingleResult(); EntityManager cn2 =
> emf.get().createEntityManager(); cn2.getTransaction().begin();
> evento e = new evento(); e.setDistrito(dist);
> Date fecha = new Date(); e.setFechaCreacion(fecha);
> try{ cn2.persist(e);
> response.getWriter().write("ok"); }finally{
> cn2.getTransaction().commit(); cn2.close(); }
> this is my entity bean Evento: @Entity public class evento implements
> Serializable { @Id @GeneratedValue(strategy =
> GenerationType.IDENTITY) Long id;
> @Temporal(javax.persistence.TemporalType.DATE) private Date
> fechaCreacion; @JoinColumn @OneToMany(cascade = CascadeType.ALL)
> private distritos distrito; --getter and setter-- Distrito: @Entity public
> class distritos implements Serializable { @Id
> @GeneratedValue(strategy = GenerationType.IDENTITY) Long id; private
> String distrito; --getter and setter-- i hope anyone help me, Thank! Johan
--
You received this message because you are subscribed to the Google Groups
"Google App Engine for Java" group.
To post to this group, send email to google-appengine-j...@googlegroups.com.
To unsubscribe from this group, send email to
google-appengine-java+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/google-appengine-java?hl=en.
