Why don’t you use a @ManyToMany relation? LieGrue, strub
> Am 26.04.2015 um 17:57 schrieb Marco de Booij <marco.developm...@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
