Question

我有一项任务是将左外连接转换为内连接。我在使用hibernate。我有实体：

@Entity
@Table("entity1")
public Entity1{
 @Id
 private Integer id;

@ManyToOne(fetch = FetchType.EAGER)
 private Entity2 field;
}

@Entity
@Table("entity2")
public class Entity2{

 @Id
 private String name;

 @ManyToOne(fetch = FetchType.EAGER)
 @JoinTable(name = "entity3_entity2",
            joinColumns = @JoinColumn(name="entity2_name")
            inverseJoinColumns = @JoinColumn(name = "entity3_name"))
 private Entity3 field;
}

@Entity
@Table("entity3")
public class Entity3{

 @Id
 private String name;

 @OneToMany
 private Set<Entity2> field;
}

我有hql：

SELECT e1 FROM Entity1 e1 inner join fetch e1.field e2 inner join fetch e2.field where e1.id = ?1

结果SQL是：

select ... from entity1 inner join entity2 on ... left outer join entity3_entity2 on ...

但是我需要在没有任何sql查询的情况下使用内部连接获取entity3记录。有办法吗？

Answer 1

要在hibernate中使用内部联接获取记录，可以使用以下查询。

<query name="findEntities">
    <query-param name="id" type="long" /> //pass id to here
    SELECT e1 FROM Entity1 e1
        inner join fetch e1.field e2 
        inner join fetch e2.field e3
    where e1 = :id
</query>

或者

@Query("SELECT e1 FROM Entity1 e1 inner join fetch e1.field e2 inner join fetch e2.field e3 where e1 = ?1")

Hibernate Inner join代替左边

1 个答案: