JPA通过SecuraryTable的一个实体和两个表

Question

我无法使以下简化设置正常工作。我只想用API标准得到一个类中表的两个值。我不想使用两个类与@OneToOne或@OneToMany等

这可能吗？JPA不打算这样做吗？

第一张表：

test.table_1(
  id integer,
  value_1 text,
  table_2_id integer
)

第二张表：

test.table_2(
  id integer,
  value_2 text
)

实体类别：

@Entity
@Table(schema = "test", name = "table_1")
@SecondaryTable(schema = "test", name = "table_2", pkJoinColumns = {
    @PrimaryKeyJoinColumn(name = "id", referencedColumnName = "table_2_id")
})
public class JointEntity {
  @Id
  private Integer id;
  @Column(name = "value_1")
  private String value1;
  @Column(name = "value_2", table = "table_2")
  private String value2;
  // getter and setter
}

执行时引发异常：

Exception in thread "main" org.hibernate.cfg.RecoverableException: Unable to find column with logical name: table_2_id in org.hibernate.mapping.Table(test.table_1) and its related supertables and secondary tables
    at org.hibernate.cfg.Ejb3JoinColumn.checkReferencedColumnsType(Ejb3JoinColumn.java:831)
    at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:608)
    at org.hibernate.cfg.annotations.EntityBinder.bindJoinToPersistentClass(EntityBinder.java:794)
    at org.hibernate.cfg.annotations.EntityBinder.createPrimaryColumnsToSecondaryTable(EntityBinder.java:786)
    at org.hibernate.cfg.annotations.EntityBinder.finalSecondaryTableBinding(EntityBinder.java:714)
    at org.hibernate.cfg.SecondaryTableSecondPass.doSecondPass(SecondaryTableSecondPass.java:29)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1621)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1586)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:858)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:885)
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39)
    at de.icybits.test.HibernatePerformanceTest.main(HibernatePerformanceTest.java:18)
Caused by: org.hibernate.MappingException: Unable to find column with logical name: table_2_id in org.hibernate.mapping.Table(test.table_1) and its related supertables and secondary tables
    at org.hibernate.cfg.Ejb3JoinColumn.checkReferencedColumnsType(Ejb3JoinColumn.java:826)
    ... 14 more

Answer 1

就像Billy Frost在他的赞扬中提到的那样，@SecuraryTable不打算以这种方式使用。所以我做了进一步的研究。因为Billy Frost的评论并没有完全回答我的问题。

1. 是否可以存档上述设置(1个实体中的2个表(

答案是肯定的我在另一个问题休眠中找到了一个解决方法-只加入单列而不是整个实体

2. JPA不打算这样做吗

正如我在1中提到的。这只是一个变通办法。一般来说，它不打算只是将单个外部列关联到一个实体。(我不能百分之百肯定这一点，但经过进一步研究，这就是我的结论。(

最后，我要感谢Billy Frost的快速评论。正因为如此，我将@SecundaryTable排除在我的研究之外，可以找到更好的答案。