Hi Johan,
you can use the Long as PK
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
Long id;
[]'s
Diego
2010/2/9 Johan Vallejo <[email protected]>
> 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 <[email protected]> <[email protected]> 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
> forbeans.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 WHEREd.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
>
>
>
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