Question

我有三个表EmployeeDepartment，EmployeeGroup和EmpplyeeDetails表。 EmployeeDepartment表具有主键departmentId和一列groupId，EmployeeGroupTable具有主键groupid，应从数据库序列GroupIdGenerator生成该主键。 EmployeeDetails有两个主键，分别是groupid和employeeid。 Groupid应与上表相同所有表中的这些值应插入一个事务中。您能帮我正确的JAP实体映射吗？

我已经尝试过使用生成值和序列生成器的不同组合，但是无法将数据保存到表中。

  @Entity
   @Table(name="EMPLOYEE_DEPARTMENT")
   public class EmployeeDepartment {

   @Column(name = "DEPARTMENT_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "departmentid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "departmentid-gen", sequenceName = 
     "DEAPARTMENT_ID_GENERATOR" )
   private  long departmentId;

   @OneToOne(mappedBy = "employeeGroup")
      private EmployeeGroup employeeGroup;
      }
  @Coulmn(name="GROUP_ID") 
  private long groupId;




   @Entity
   @Table(name="EMPLOYEE_GROUP")
   public class EmployeeGroup {

   @Column(name = "GROUP_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "groupid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "groupid-gen", sequenceName = 
     "GROUIP_ID_GENERATOR" )
   private  long groupId;

   @OneToMany(mappedBy = "employeeDetail")
      private List<EmployeeDetail> employeeDetails;

  @OneToOne
  @JoinColumn(name = "DEPARTMENT_ID", insertable=false , 
        updatable=false)
      private EmployeeDepartment employeeDepatment;
      }



@Entity
   @Table(name = "EMPLOYEE_DETAIL")
   @IdClass(EmployeeID.class)
   public class EmployeeDetail {

  @ManyToOne
  @JoinColumn(name = "GROUP_ID", insertable=false , updatable=false)
  private EmployeeGroup employeeGroup;

  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
     "groupid-gen")
  @SequenceGenerator(name = "groupid-gen", sequenceName = 
    "GROUIP_ID_GENERATOR" )
  @Column(name = "GROUP_ID")
  @Nonnull
     private Long groupId;

  @Id
  @Nonnull
  @Column(name = "EMPLOYEE_ID")
    private Long employeeId;

}

public class EmployeeId{

private Long groupId;

private Long employeeId;

public EmployeeId(final Long groupId, final Long employeeId) {
    this.groupId = groupId;
    this.employeeId = employeeId;
}

public EmployeeId() {
}

}

这3个表中的预期结果应具有适当的值。

表EmployeeDepartment

DepartmentID   GroupId
   1               1

表EmployeeGroup

 GroupID  
   1

表EmployeeDetail

GroupId       EmployeeId
  1            1
  1            2
  1            3

实际结果如下

表EmployeeDepartment

DepartmentID   GroupId
   1               0

表EmployeeGroup

 GroupID  
   1

表EmployeeDetail

GroupId       EmployeeId
  2            1
  3            2
  4            3

Answer 1

重要的注释是@MapsId("groupId")

您的映射应如下所示：

   @Entity
   @Table(name="EMPLOYEE_DEPARTMENT")
   public class EmployeeDepartment {

   @Column(name = "DEPARTMENT_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "departmentid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "departmentid-gen", sequenceName = 
     "DEAPARTMENT_ID_GENERATOR" )
   private  long departmentId;

   @OneToOne(mappedBy = "employeeGroup")
   private EmployeeGroup employeeGroup;

   @Column(name="GROUP_ID") 
   private long groupId;


   @Entity
   @Table(name="EMPLOYEE_GROUP")
   public class EmployeeGroup {

   @Column(name = "GROUP_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "groupid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "groupid-gen", sequenceName = 
     "GROUIP_ID_GENERATOR" )
   private  long groupId;

   @OneToMany(mappedBy = "employeeDetail")
   private List<EmployeeDetail> employeeDetails;

   @OneToOne
   @JoinColumn(name = "DEPARTMENT_ID", insertable=false, updatable=false)
   private EmployeeDepartment employeeDepatment;


   @Entity
   @Table(name = "EMPLOYEE_DETAIL")
   @IdClass(EmployeeID.class)
   public class EmployeeDetail {

   @MapsId("groupId")
   @ManyToOne
   @JoinColumn(name = "GROUP_ID", insertable=false , updatable=false)
   private EmployeeGroup employeeGroup;

   @Id
   @Nonnull
   @Column(name = "EMPLOYEE_ID")
   private Long employeeId;

Answer 2

 @Entity
   @Table(name="EMPLOYEE_DEPARTMENT")
   public class EmployeeDepartment {

   @Column(name = "DEPARTMENT_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "departmentid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "departmentid-gen", sequenceName = 
     "DEAPARTMENT_ID_GENERATOR" )
   private  Long departmentId;

   @OneToOne(mappedBy = "employeeGroup")
      private EmployeeGroup employeeGroup;
      }
  @Column(name="GROUP_ID") 
  private EmployeeGroup group;




   @Entity
   @Table(name="EMPLOYEE_GROUP")
   public class EmployeeGroup {

   @Column(name = "GROUP_ID")
   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = 
      "groupid-gen")
   @Id
   @NotNull
   @SequenceGenerator(name = "groupid-gen", sequenceName = 
     "GROUIP_ID_GENERATOR" )
   private  Long groupId;

   @OneToMany(mappedBy = "employeeDetail")
      private List<EmployeeDetail> employeeDetails;

  @OneToOne
  @JoinColumn(name = "DEPARTMENT_ID", insertable=false , 
        updatable=false)
      private EmployeeDepartment employeeDepatment;
      }



@Entity
   @Table(name = "EMPLOYEE_DETAIL")
   @IdClass(EmployeeID.class)
   public class EmployeeDetail {

  @Id
  @ManyToOne
  @JoinColumn(name = "GROUP_ID", insertable=false , updatable=false)
  private EmployeeGroup employeeGroup;

  @Id
  @Nonnull
  @Column(name = "EMPLOYEE_ID")
    private Long employeeId;

您还需要相应地更改EmployeeId：

public class EmployeeId{

private EmployeeGroup employeeGroup;

private Long employeeId;

public EmployeeId(final EmployeeGroup employeeGroup, final Long employeeId) {
    this.employeeGroup= employeeGroup;
    this.employeeId = employeeId;
}

但是我以前从未以这种方式使用复合键。如果不起作用，则将EmployeeId更改为EmbeddedId：

@Embeddable
public class EmployeeId implements Serializable{

@ManyToOne(fetch = FetchType.LAZY, optional = false)
private EmployeeGroup employeeGroup;

@Nonnull
@Column(name = "EMPLOYEE_ID")
private Long employeeId;

public EmployeeId(final EmployeeGroup employeeGroup, final Long employeeId) {
    this.employeeGroup= employeeGroup;
    this.employeeId = employeeId;
}


@Entity
@Table(name = "EMPLOYEE_DETAIL")
public class EmployeeDetail {

  @EmbeddedId
  private EmployeeId id;

  @ManyToOne
  @JoinColumn(name = "GROUP_ID", insertable=false , updatable=false)
  private EmployeeGroup employeeGroup;

}

如果仍然无法使用，请在创建实体的地方附加代码段。

连接列的JPA实体映射

2 个答案: