如何在Hibernate中通过不同名称的非PK列映射2个表

Question

@Entity
@Table(name = "PLANS_T")
public class Plans {
    private Integer id; // PK
    //...
    private String secondaryIdentifier; // Should be matched with TRAINEES.auxiliaryIdentifier
    //...
}

@Entity
@Table(name = "TRAINEES_T")
public class Trainee {    
    private Integer id; // PK
    //...
    private String auxiliaryIdentifier; // Should be matched with PLANS.secondaryIdentifier
}

但是我不能用典型的例子。

@Entity
class Trainee {

    @OneToMany(mappedBy = "plan")
    private Collection<Plans> plans = new ArrayList<Plans>();

}

@Entity
class Plans {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name="auxiliary_identifier") // Where do I specify "secondaryIdentifier", a non-PK column?
    private Trainee trainee;

}

我需要一种方法在注释中指定两个非PK列。使用条件API时，这些注释提供了创建联接路径的路径。

Answer 1

您应该按照以下方式更正您的映射：

@Entity
class Trainee {

   @OneToMany(mappedBy = "trainee")
   private List<Plans> plans = new ArrayList<Plans>();
}

@Entity
class Plans {

   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumn(name="secondary_identifier", referencedColumnName = "auxiliary_identifier")
   private Trainee trainee;

}

>

@OneTomany的MappedBy是拥有该关系的字段的名称。这是plans实体的trainee字段。

@JoinColumn的referencedColumnName是此外键列引用的列的名称。