Question

我遇到了JPA和ManyToMany协会的问题。

我有两个类FOA_PARAM_EMPLOYE和FOA_PARAM_POSITION，以及一个关联表FOA_PARAM_EMPLOYE_POSITION。

Class FoaParamEmploye：

@Entity
@Table(name = "FOA_PARAM_EMPLOYE")
@NamedQuery(name = "FoaParamEmploye.findAll", query = "SELECT f FROM FoaParamEmploye f")
public class FoaParamEmploye implements Serializable {
private static final long serialVersionUID = 1L;

@EmbeddedId
private FoaParamEmployePK id;

@Column(name = "ACTEUR_MAJ_OCCUR")
private String acteurMajOccur;

@Column(name = "ADRESSE_EMAIL")
private String adresseEmail;

// bi-directional many-to-many association to FoaParamPosition
@ManyToMany
@JoinTable(
        name = "FOA_PARAM_EMPLOYE_POSITION", 
        joinColumns = { @JoinColumn(name = "ID_EMPLOYE"),
                        @JoinColumn(name = "COD_ENTREP") }, 
        inverseJoinColumns = { @JoinColumn(name = "ID_POSITION")
})
private List<FoaParamPosition> foaParamPositions;

public FoaParamEmployePK getId() {
    return this.id;
}

public void setId(FoaParamEmployePK id) {
    this.id = id;
}

public String getActeurMajOccur() {
    return this.acteurMajOccur;
}

public void setActeurMajOccur(String acteurMajOccur) {
    this.acteurMajOccur = acteurMajOccur;
}

public String getAdresseEmail() {
    return this.adresseEmail;
}

public void setAdresseEmail(String adresseEmail) {
    this.adresseEmail = adresseEmail;
}

public List<FoaParamPosition> getFoaParamPositions() {
    return foaParamPositions;
}

public void setFoaParamPositions(List<FoaParamPosition> pFoaParamPositions) {
    this.foaParamPositions = pFoaParamPositions;
}
}

Class FoaParamPosition：

@Entity
@Table(name="FOA_PARAM_POSITION")
@NamedQuery(name="FoaParamPosition.findAll", query="SELECT f FROM FoaParamPosition f")
public class FoaParamPosition implements Serializable {
private static final long serialVersionUID = 1L;

@EmbeddedId
private FoaParamPositionPK id;

@Column(name="ACTEUR_MAJ_OCCUR")
private String acteurMajOccur;

@Column(name="CD_PROFIL_AFFECTATION")
private String cdProfilAffectation;

// bi-directional many-to-many association to FoaParamEmploye
@ManyToMany
private List<FoaParamEmploye> foaParamEmployes;

public FoaParamPositionPK getId() {
    return this.id;
}

public void setId(FoaParamPositionPK id) {
    this.id = id;
}

public String getActeurMajOccur() {
    return this.acteurMajOccur;
}

public void setActeurMajOccur(String acteurMajOccur) {
    this.acteurMajOccur = acteurMajOccur;
}

public String getCdProfilAffectation() {
    return this.cdProfilAffectation;
}

public void setCdProfilAffectation(String cdProfilAffectation) {
    this.cdProfilAffectation = cdProfilAffectation;
}

public List<FoaParamEmploye> getFoaParamEmployes() {
    return foaParamEmployes;
}

public void setFoaParamEmployes(List<FoaParamEmploye> pFoaParamEmployes) {
    this.foaParamEmployes = pFoaParamEmployes;
}
}

表FOA_PARAM_EMPLOYE_POSITION有以下列：

COD_ENTREP
ID_EMPLOYE
ID_POSITION
XQCIF
ACTEUR_MAJ_OCCUR
DATE_HEURE_MAJ_OCCUR

我遇到了这个例外：

A Foreign key refering com.groupama.middlgan.entities.FoaParamPosition from
com.groupama.middlgan.entities.FoaParamEmploye has the wrong number of column. 
should be 2

如果我在我的FoaParamEmploye实体的inverseJoinColumns上添加COD_ENTREP，我得到了这个例外：

Repeated column in mapping for collection: 
com.groupama.middlgan.entities.FoaParamEmploye.foaParamPositions column: COD_ENTREP

任何想法？

Answer 1

[我假设您列出了关联表FOA_PARAM_EMPLOYE_POSITION的列，而不是FOA_PARAM_EMPLOYE，正如您在问题中所述。]

您的映射暗示FOA_PARAM_EMPLOYE_POSITION.COD_ENTREP是两个外键的一部分，一个引用FOA_PARAM_EMPLOYE，另一个引用FOA_PARAM_POSITION。实际上，这两个外键可能包含COD_ENTREP的相同值，但数据库或JPA无法强制执行此操作。

您可能应该以不同的方式对关系进行建模，可能会添加另一个类似于容器的对象，该对象与FoaParamEmploye和FoaParamPosition具有双向一对多关系并共享其主要部分键与其他两个主键。

Answer 2

如果要保留inverseJoinColumn映射，可以执行以下操作，

@ManyToMany
@JoinTable(
    name = "FOA_PARAM_EMPLOYE_POSITION", 
    joinColumns = { @JoinColumn(name = "ID_EMPLOYE"),
                    @JoinColumn(name = "COD_ENTREP") }
,
        inverseJoinColumns = {@JoinColumn(name = "FOAPARAMPOSITION_COD_ENTREP"), @JoinColumn(name = "FOAPARAMPOSITION_ID_POSITION")}
)
private List<FoaParamPosition> foaParamPosition;

和

@ManyToMany
@JoinTable(
    name = "FOA_PARAM_EMPLOYE_POSITION", 
    joinColumns = { @JoinColumn(name = "ID_POSITION"),
                    @JoinColumn(name = "COD_ENTREP") }
        ,
        inverseJoinColumns = {@JoinColumn(name = "FOAPARAMEMPLOYE_COD_ENTREP"), @JoinColumn(name = "FOAPARAMEMPLOYE_ID_EMPLOYE")}

)
private List<FoaParamEmploye> foaParamEmploye;

映射与您在其他问题JPA Many To Many Select

中发布的代码一致

外键引用的列数错误

2 个答案: