Hi Jacek,
Based on that description, it sounds like a bug in OpenJPA's list
handling somewhere.
Do the SQL statements issued differ?
-Patrick
On 11/28/07, Jacek Laskowski <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I've got two entities: Osoba (Whole) and Konto (Part) in OneToMany
> association. Each contains id and name attributes. I decided to test
> inner and left fetch joins.
>
> I created 2 Osoba's, but only one got 2 Konto's.
>
> When I run
>
> SELECT o FROM Osoba o
>
> it returns 2 entities which is fine. However, when I run
>
> SELECT o FROM Osoba o JOIN FETCH o.konta
>
> it returns 1 entity which is still fine but the number of Konta
> entities is...4 (!).
>
> When I changed the type of Osoba.konta (plural of konto in Polish)
> from List<Konto> to Set<Konto> the above query returned 2 which was
> what I had first expected.
>
> Could anyone explain it to me? I seem to be missing some SQL classes
> on how joins are supposed to work so any pointers to documentation
> would be fine too.
>
> Here the entities go (with Set<Konto>):
>
> package pl.jaceklaskowski.jpa;
>
> import java.io.Serializable;
> import java.util.HashSet;
> import java.util.Set;
> import javax.persistence.CascadeType;
> import javax.persistence.Entity;
> import javax.persistence.GeneratedValue;
> import javax.persistence.GenerationType;
> import javax.persistence.Id;
> import javax.persistence.NamedQueries;
> import javax.persistence.NamedQuery;
> import javax.persistence.OneToMany;
>
> @Entity
> @NamedQueries({
> @NamedQuery(name = "Osoba.poImieniu", query = "SELECT o FROM Osoba
> o WHERE o.imie = :imie"),
> @NamedQuery(name = "Osoba.wszystkieOsoby", query = "SELECT o FROM Osoba
> o"),
> @NamedQuery(name = "Osoba.wszystkieOsoby.JOIN_FETCH", query =
> "SELECT o FROM Osoba o JOIN FETCH o.konta"),
> @NamedQuery(name = "Osoba.wszystkieOsoby.LEFT_JOIN_FETCH", query =
> "SELECT o FROM Osoba o LEFT JOIN FETCH o.konta")
> })
> public class Osoba implements Serializable {
>
> private static final long serialVersionUID = 1L;
> private int id;
> private String imie;
> private Set<Konto> konta = new HashSet<Konto>();
>
> protected Osoba() {
> }
>
> public Osoba(String imie) {
> this.imie = imie;
> }
>
> @Id
> @GeneratedValue(strategy = GenerationType.AUTO)
> public int getId() {
> return id;
> }
>
> public void setId(int id) {
> this.id = id;
> }
>
> @OneToMany(cascade=CascadeType.PERSIST)
> public Set<Konto> getKonta() {
> return konta;
> }
>
> public void setKonta(Set<Konto> konta) {
> this.konta = konta;
> }
>
> public void addKonto(Konto konto) {
> getKonta().add(konto);
> }
>
> public String getImie() {
> return imie;
> }
>
> public void setImie(String imie) {
> this.imie = imie;
> }
>
> @Override
> public String toString() {
> return "Osoba[id=" + getId() + "]";
> }
> }
>
> package pl.jaceklaskowski.jpa;
>
> import java.io.Serializable;
> import javax.persistence.Entity;
> import javax.persistence.GeneratedValue;
> import javax.persistence.GenerationType;
> import javax.persistence.Id;
>
> @Entity
> public class Konto implements Serializable {
>
> private static final long serialVersionUID = 1L;
> private int id;
> private String numer;
>
> protected Konto() {
> }
>
> public Konto(String numer) {
> this.numer = numer;
> }
>
> @Id
> @GeneratedValue(strategy = GenerationType.AUTO)
> public int getId() {
> return id;
> }
>
> public void setId(int id) {
> this.id = id;
> }
>
> public String getNumer() {
> return numer;
> }
>
> public void setNumer(String numer) {
> this.numer = numer;
> }
>
> @Override
> public String toString() {
> return "Konto[id=" + getId() + "]";
> }
> }
>
> Jacek
>
> --
> Jacek Laskowski
> http://www.JacekLaskowski.pl
>
--
Patrick Linskey
202 669 5907
