Why don’t you use a @ManyToMany relation?
LieGrue,
strub
> Am 26.04.2015 um 17:57 schrieb Marco de Booij <marco.development@debooy.eu>:
>
> I use Tomee 1.7.1 with openjpa version openjpa-2.4.0-nonfinal-1598334-r422266.
>
> I have an entity auteurs and an entity boek. They have a ManyToMany relation through
the entity auteurs_boeken. In this entity there is a field type to define the type of the
relation (writer, illustrations, ...). I followed the https://en.wikibooks.org/wiki/Java_Persistence/ManyToMany
page and came up with the following classes (left out all constructors, getters, and setters):
>
> =====
> @Entity
> @Table(name="AUTEURS", schema="BYBLOS")
> public class AuteurDto
> extends Dto implements Comparable<AuteurDto>, Cloneable {
> private static final long serialVersionUID = 1L;
>
> @Id
> @GeneratedValue(strategy=GenerationType.IDENTITY)
> @Column(name="AUTEUR_ID", nullable=false, unique=true)
> private Long auteurId;
> @Column(name="NAAM", length=100, nullable=false)
> private String naam;
> @Column(name="VOORNAAM", length=100)
> private String voornaam;
>
> @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.LAZY, mappedBy="auteur")
> private List<AuteurBoekDto> boeken;
> }
>
> =====
> @Entity
> @Table(name="BOEKEN", schema="BYBLOS")
> public class BoekDto extends Dto implements Comparable<BoekDto>, Cloneable {
> private static final long serialVersionUID = 1L;
>
> @Id
> @GeneratedValue(strategy=GenerationType.IDENTITY)
> @Column(name="BOEK_ID", nullable=false, unique=true)
> private Long boekId;
> @Column(name="DEEL", precision=5, scale=0)
> private Integer deel;
> @Column(name="DRUK", precision=3, scale=0)
> private Integer druk;
> @Column(name="ISBN", length=13)
> private String isbn;
> @Column(name="JAAR_UITGAVE", precision=4, scale=0)
> private Integer jaarUitgave;
> @Column(name="SUBDEEL", length=2)
> private String subdeel;
> @Column(name="TAAL", length=2, nullable=false)
> private String taal;
> @Column(name="TITEL", length=100, nullable=false)
> private String titel;
>
> @OneToOne(cascade=CascadeType.ALL, fetch=FetchType.LAZY)
> @JoinColumn(name="SERIE_ID", nullable=false, updatable=false)
> private SerieDto serie;
>
> @OneToMany(mappedBy="boek", fetch=FetchType.LAZY)
> private List<AuteurBoekDto> auteurs;
> }
>
> =====
> @Entity
> @Table(name="AUTEURS_BOEKEN", schema="BYBLOS")
> @IdClass(AuteurBoekPK.class)
> public class AuteurBoekDto
> extends Dto implements Comparable<AuteurBoekDto>, Cloneable {
> private static final long serialVersionUID = 1L;
>
> @Id
> private Long auteurId;
> @Id
> private Long boekId;
> @Column(name="AUTEUR_TYPE", nullable=false, length=1)
> private String auteurType;
>
> @ManyToOne
> @PrimaryKeyJoinColumn(name="AUTEUR_ID", referencedColumnName="auteurId")
> private AuteurDto auteur;
> @ManyToOne
> @PrimaryKeyJoinColumn(name="BOEK_ID", referencedColumnName="boekId")
> private BoekDto boek;
> }
>
> When I fetch the boeken from within the AuteurDto I get the message:
> <openjpa-2.4.0-nonfinal-1598334-r422266:1599166 fatal user error> org.apache.openjpa.persistence.ArgumentException:
"eu.debooy.byblos.domain.AuteurBoekDto.auteur" defines a target of "auteurId" for column "AUTEUR_ID",
but that target does not exist in table "BYBLOS.AUTEURS".
> I have the same problem on the BoekDto. BoekDto has a OneToOne relation with SerieDto
and when I read the boeken from there I get the correct boeken so I guess that the problem
lies with my implementation of the ManyToMany. Can someone show me the way to the correct
implementation?
>
> Regards,
>
> Marco
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