java - JPA/hibernate 。如何防止自动继承字段get的类前缀

Question

以下情况:当我尝试保存带有 @EmbeddedId 字段的实体时，hibernate 使该字段从基类“mandant”变为“contact_mandant”，并抛出无效标识符错误。表“Contact”中的列名称是“mandant”，而不是“contact_mandat”。 我只是不明白为什么字段名称会自动更改。 这里有一些代码:

    @MappedSuperclass
    public abstract class BaseId implements Serializable {

      @Column(name = "Mandant", precision = 2, nullable = false)
      protected Byte mandant;

      ...getter, setter...
    }

    @Embeddable
    public class ContactId extends BaseId implements Serializable {

       @Column(name = "Id_Contact", precision = 9)
       private Long id;

      ...getter, setter...
    }

    @Entity
    public class Contact extends Base {

      @EmbeddedId
      private ContactId contactId;

      ...getter, setter...
    }

   @Entity(name = "Employee")
   public class Employee extends Base {

    @EmbeddedId
    private EmployeeId id;

    @MapsId("contactId")
    @JoinColumns(value = {
            @JoinColumn(referencedColumnName = "Mandant"),
            @JoinColumn(referencedColumnName = "Id_Contact")
    })
    @OneToOne(fetch = FetchType.LAZY)
    private Contact contact;

       ...getter, setter...
    }

   @Embeddable
   public class EmployeeId extends BaseId implements Serializable {

     @Column(name = "Id_Employee", precision = 9)
     private Long id;

     private ContactId contactId;

      ...getter, setter...
    }

我来自 .Net 世界，对 JPA 还不太熟悉。有人可以友好地提示我做错了什么或者问题出在我的实现上吗？

最诚挚的问候 新闻记者

附注:Spring 4 和 Hibernate 5

Answer 1

使用共享复合 key 的解决方案:

@MapsId 中如果没有“id”，框架会生成以下查询:

“插入 EMPLOYEE_DETAILS (AEN_DATUM、SACHB_KZ、DETAILS、employee_id_employee、employee_MANDANT) 值 (?, ?, ?, ?, ?)”

将“id”添加到@MapsId后，查询为:

“插入 EMPLOYEE_DETAILS (AEN_DATUM、SACHB_KZ、DETAILS、id_employee、MANDANT) 值 (?, ?, ?, ?, ?)”

@Entity(name = "Employee")
@Table(name = "EMPLOYEE")
public class Employee extends Base {

    @EmbeddedId
    private EmployeeId id;

    @Column(name = "FIRST_NAME", length = 100, nullable = false)
    private String firstName;

    @Column(name = "SUR_NAME", length = 100, nullable = false)
    private String surName;
...
}

@Embeddable
public class EmployeeId extends BaseId implements Serializable {

    @Column(name = "id_employee", precision = 9)
    private Long employeeId;
...
}

@Entity(name = "EmployeeDetails")
@Table(name = "EMPLOYEE_DETAILS")
public class EmployeeDetails extends Base {

    @EmbeddedId
    private EmployeeId id;

    @Column(name = "DETAILS", nullable = false)
    private String details;

    @MapsId("id")
    @OneToOne
    private Employee employee;
...
}

这与上面的实现不同，但问题是一样的。该查询是使用 CONTACT_MANDANT 而不是 MANDANT 生成的。

和平