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Delete from collection [message #537417]

Wed, 02 June 2010 12:05

Pavel Zelenka

Messages: 61
Registered: July 2009

Member

Hi,

it's probably a newbie question but I can't help myself. If I remove object from collection actors, I want this was deleted from database too.

@Entity
public class Movie implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer idmovie;
   @OneToMany(fetch = FetchType.EAGER, mappedBy = "movie", cascade = CascadeType.ALL)
    private List<Actor> actors;

@Entity
public class Actor implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer idactor;
   @ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.ALL)
    @JoinColumn(name = "idmovie")
    private Movie movie;

I remove the entity this way:

movie.getActors().remove(actor);
actor.setMovie(null);

and later when I want to persist into database

EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
em.merge(movie);
em.getTransaction().commit();
em.close();

Any help appreciated.

Thanks

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Re: Delete from collection [message #537533 is a reply to message #537417]

Wed, 02 June 2010 19:09

Gilberto Caetano de Andrade

Messages: 45
Registered: July 2009

Member

Hi,

from persistence-2_0-final-spec:

Quote:

Bidirectional relationships between managed entities will be persisted based on references held by the
owning side of the relationship. It is the developer's responsibility to keep the in-memory references
held on the owning side and those held on the inverse side consistent with each other when they change.
In the case of unidirectional one-to-one and one-to-many relationships, it is the developer's responsibil-
ity to insure that the semantics of the relationships are adhered to.

This one is may test:

    @Test
    public void romeveBidirectional() throws Exception {
        log.debug("\nGetting an Vehicle by ID.\n");
        Vehicle v = em.find(Vehicle.class, "LC100");
        log.debug("Object loaded: \n" + v);
        assertEquals(v.getColor(), "RED");
        assertEquals("Should have 2 stays", v.getStays().size(), 2);
        for (Stay s : v.getStays()) {
            if (s.getId().equals(100)) {
                v.getStays().remove(s);
                s.setVehicle(null);
            }
        }
        //Another way:
        //Stay s = em.find(Stay.class, 100);
        //v.getStays().remove(s);
        //s.setVehicle(null);

        tx.begin();
        em.merge(v);
        tx.commit();
        assertEquals("Should have 1 stays", v.getStays().size(), 1);
    }

Gilberto

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