Question

我有两个实体FoaParamEmploye和FoaParamPosition（表FOA_PARAM_EMPLOYE和FOA_PARAM_POSITION）和ManyToMany注释（我没有把所有属性放在这里）：

@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;

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

第二个：

@Entity
@Table(name="FOA_PARAM_POSITION")
@NamedQuery(name="FoaParamPosition.findAll", query="SELECT f FROM FoaParamPosition f")
public class FoaParamPosition implements Serializable {

    @EmbeddedId
    private FoaParamPositionPK id;

    @ManyToMany
    @JoinTable(
        name = "FOA_PARAM_EMPLOYE_POSITION", 
        joinColumns = { @JoinColumn(name = "ID_POSITION"),
                        @JoinColumn(name = "COD_ENTREP") }
    )
    private List<FoaParamEmploye> foaParamEmployes;
}

关联表格为FOA_PARAM_EMPLOYE_POSITION，其中包含COD_ENTREP，ID_POSITION和ID_EMPLOYE字段。

PK是：

@Embeddable
public class FoaParamEmployePK implements Serializable {
    //default serial version id, required for serializable classes.
     private static final long serialVersionUID = 1L;

     @Column(name="COD_ENTREP")
    private String codEntrep;

    @Column(name="ID_EMPLOYE")
    private long idEmploye;
}

@Embeddable
public class FoaParamPositionPK implements Serializable {
    //default serial version id, required for serializable classes.
    private static final long serialVersionUID = 1L;

    @Column(name="COD_ENTREP")
    private String codEntrep;

    @Column(name="ID_POSITION")
    private long idPosition;
}

我尝试为FoaParamEmploye获取所有FoaParamPosition。我写了这个JPQL查询：

Query q = entityMgr.createQuery(
    "SELECT position FROM FoaParamPosition position 
     INNER JOIN position.foaParamEmployes employes 
     where 
     employes.id.idEmploye = :idEmploye AND 
     employes.id.codEntrep =:codEntrep")
.setParameter("idEmploye", pIdEmploye)
.setParameter("codEntrep", "ENT");

我有一个例外：

ORA-00904: "FOAPARAMEM1_"."FOAPARAMEMPLOYES_ID_EMPLOYE" : non valid identifier

如您所见，生成SQL具有此属性，但我无法理解原因：

select
    foaparampo0_.COD_ENTREP as COD1_2337_,
    foaparampo0_.ID_POSITION as ID2_2337_,
    foaparampo0_.ACTEUR_MAJ_OCCUR as ACTEUR3_2337_,
    foaparampo0_.CD_PROFIL_AFFECTATION as CD4_2337_,
    foaparampo0_.CD_TYPE_PROFIL_POSITION as CD5_2337_,
    foaparampo0_.DATE_HEURE_MAJ_OCCUR as DATE6_2337_,
    foaparampo0_.DT_FIN_ACTIVITE_POSITION as DT7_2337_,
    foaparampo0_.HIERARCHIE_POSITION as HIERARCHIE8_2337_,
    foaparampo0_.ID_DIVISION_AGENCE as ID9_2337_,
    foaparampo0_.ID_EMPLOYE_PRINCIPAL as ID10_2337_,
    foaparampo0_.ID_REF_EXT_POSITION_PARENTE as ID11_2337_,
    foaparampo0_.ID_REF_EXTERNE_POSITION as ID12_2337_,
    foaparampo0_.NIVEAU_AGENCE as NIVEAU13_2337_,
    foaparampo0_.REF_EXT_POSITION as REF14_2337_,
    foaparampo0_.xqcif as xqcif2337_ 
from
    FOA_PARAM_POSITION foaparampo0_,
    FOA_PARAM_EMPLOYE_POSITION foaparamem1_,
    FOA_PARAM_EMPLOYE foaparamem2_ 
where
    foaparampo0_.COD_ENTREP=foaparamem1_.ID_POSITION 
    and foaparampo0_.ID_POSITION=foaparamem1_.COD_ENTREP 
    and foaparamem1_.foaParamEmployes_COD_ENTREP=foaparamem2_.COD_ENTREP 
    and foaparamem1_.foaParamEmployes_ID_EMPLOYE=foaparamem2_.ID_EMPLOYE 
    and foaparamem2_.ID_EMPLOYE=? 
    and foaparamem2_.COD_ENTREP=?

Answer 1

我建议您使用某些工具映射您的课程，例如Netbeans - ＆gt;生成JPA实体。你的一方必须拥有一方（JoinColumn），一方必须是反方（mappedBy）。

如果您不想使用任何地图绘制工具，请参阅：

http://alextretyakov.blogspot.cz/2013/07/jpa-many-to-many-mappings.html

Answer 2

我不确定，但我想如果首先通过 JPA 查询获得 FoaParamEmploye 对象，之后使用 getFoaParamPosition 方法此对象检索您的问题将得到解决的位置列表（在多对多关联中使用此方法时，JPA将自动检索列表）：

Select distinct f from FoaParamEmployes f 
 where f.employes.idEmploye = :idEmploye

Answer 3

我没有在您的地图中看到问题。您收到的错误明确抱怨无效的列名称。在Oracle中，引用的名称（如"FOAPARAMPO0_"."FOAPARAMPOSITIONS_ID_POSITION"）区分大小写，而生成的列为foaParamPositions_COD_ENTREP和foaParamPositions_ID_POSITION且大小写不匹配会导致您的错误。

快速检查将大写 foaParamEmployes 和 foaParamPositions ，如果我是对的，则应解决上述问题。如果是这样，您可以使用更优雅的方法来控制使用映射生成的名称。

我在注释中注意到你的其他问题，指的是 inverseJoinColumns 的问题。这就是为什么我提到你的房产上层。但事实上，你可以使用像

这样的映射来处理它

@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;

解决了你的其他question我认为的问题

JPA多对多选择

3 个答案: