为什么Spring Data JPA + Hibernate生成不正确的SQL？ [英] Why does Spring Data JPA + Hibernate generate incorrect SQL?

问题描述

我有两个具有一对多关系的实体。我想获得与其他实体集合相关的所有实体
。这是我的课程：

 公共类实例{
 
 @Id 
 @GeneratedValue 
私人长ID; 
 
 @OneToMany（mappedBy =instance）
 private Set< Action> actions = new HashSet<>（）; 
 
} 
 
公共类动作{
 
 @Id 
 @GeneratedValue 
私人长ID; 
 
 @ManyToOne 
 @JoinColumn（name =instance_id）
私有实例实例; 
 
} 
  

另外我有以下资源库：

  public interface InstanceRepository扩展了JpaRepository< Instance，Long> {
 
列表< Instance> findByActions（Set< Action> actions）; 
 
 
  

当我用空或单元素集调用方法时，我没有得到任何错误。但是如果该集合包含更多元素
，我会得到一个异常。 MySQL表示操作数应该包含1列（s）。为空或单元素
集生成的SQL是

  select instance0_.id as id1_3_ 
 from instance instance0_ 
在instance0_.id = actions1_.instance_id 
其中actions1_.id =？左边的外部连接操作actions1_ 
 
  

和其他集合

  select instance0_.id as id1_3_ 
 from instance instance0_ 
 left outer join action actions1_ 
 on instance0_.id = actions1_.instance_id 
 where actions1_.id = （？，？，？，...）
  

这显然是错误的，它应该是

  select instance0_.id as id1_3_ 
 from instance instance0_ 
 left outer join action actions1_ 
 on instance0_.id = actions1_.instance_id 
 where（？，？，？，...）中的actions1_.id 
  

为什么Hibernate会生成这个SQL，我该如何解决它？为什么Hibernate会生成这个SQL，我该如何解决它？

规格您必须将此方法定义为：

  List< Instance> findByActionsIn（Collection< Action> actions）; 
  

I have two entities with a one-to-many relationship. I want to get all entities that are tied to a set of the other entity. This are my classes:

public class Instance {

    @Id
    @GeneratedValue
    private long id;

    @OneToMany(mappedBy = "instance")
    private Set<Action> actions = new HashSet<>();

}

public class Action {

    @Id
    @GeneratedValue
    private long id;

    @ManyToOne
    @JoinColumn(name = "instance_id")
    private Instance instance;

}

Furthermore I have the following repository:

public interface InstanceRepository extends JpaRepository<Instance, Long> {

    List<Instance> findByActions(Set<Action> actions);

}

When I call the method with empty or single element sets, I get no errors. But if the set contains more elements I get an exception. MySQL says Operand should contain 1 column(s). The generated SQL for empty or single element sets is

select instance0_.id as id1_3_
from instance instance0_
left outer join action actions1_
on instance0_.id=actions1_.instance_id
where actions1_.id=?

and for other sets

select instance0_.id as id1_3_
from instance instance0_
left outer join action actions1_
on instance0_.id=actions1_.instance_id
where actions1_.id=(?, ?, ?, ...)

This is obviously wrong and it should be something like

select instance0_.id as id1_3_
from instance instance0_
left outer join action actions1_
on instance0_.id=actions1_.instance_id
where actions1_.id in (?, ?, ?, ...)

Why does Hibernate generate this SQL and how do I fix it?

解决方案

According to the Spring Data spec you have to define this method as:

List<Instance> findByActionsIn(Collection<Action> actions);

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