Spring Data JPA: Repository的DeleteById方法无法工作

Question

Spring Data JPA: Repository的DeleteById方法无法工作

7

我是一位有用的助手，可以为您翻译内容。以下是需要翻译的IT技术相关内容：

我在使用Spring Data JPA存储库时遇到了一个问题，但我不明白它的原因。我有以下实体:


@Entity
public class Ability {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;
    private String name;
    private String color;
    private String image;

    @ManyToOne(
            fetch = FetchType.EAGER
    )
    private Subject subject;

    @OneToMany(
            mappedBy = "ability",
            cascade = CascadeType.ALL,
            orphanRemoval = true,
            fetch = FetchType.EAGER
    )
    private Set<Technology> technologies;

针对这个实体，需要一个JPA存储库。我不理解的是，当我使用Jpa存储库的deleteById方法时，记录并没有从数据库中删除。奇怪的是，在使用内存数据库的集成测试中，它可以正常工作。如果我使用以下代码覆盖deleteById，则可以正常工作：

    @Modifying
    @Query("DELETE FROM Ability a WHERE a.id = :id")
    void deleteById(@Param("id") Integer id);

但我怀疑我不应该这样做。有没有任何线索表明该方法不能按预期工作？

编辑：添加端点源代码

@RestController
@RequestMapping("/subjects/{subjectId}/abilities")
public class AbilityController {
    ...
    
    private final AbilityRepository abilityRepository;
    private final TechnologyRepository technologyRepository;
    private final SubjectRepository subjectRepository;

    public AbilityController(AbilityRepository abilityRepository, TechnologyRepository technologyRepository, SubjectRepository subjectRepository) {
        this.abilityRepository = abilityRepository;
        this.technologyRepository = technologyRepository;
        this.subjectRepository = subjectRepository;
    }

    @DeleteMapping("{abilityId}")
    @ResponseStatus(HttpStatus.NO_CONTENT)
    public void deleteAbility(@PathVariable("subjectId") Integer subjectId, @PathVariable("abilityId") Integer abilityId) {
        if (!abilityRepository.existsAbilityBySubjectId(subjectId, abilityId)) {
            throw new ResourceNotFoundException(String.format("No ability with Id : %s", abilityId));
        }

        abilityRepository.deleteById(abilityId);
    }
    ...
}

编辑：添加Hibernate SQL

Hibernate: 
    select
        ability0_.id as id1_0_0_,
        ability0_.color as color2_0_0_,
        ability0_.image as image3_0_0_,
        ability0_.name as name4_0_0_,
        ability0_.subject_id as subject_5_0_0_,
        subject1_.id as id1_7_1_,
        subject1_.icon as icon2_7_1_,
        subject1_.image as image3_7_1_,
        subject1_.name as name4_7_1_,
        technologi2_.ability_id as ability_4_8_2_,
        technologi2_.id as id1_8_2_,
        technologi2_.id as id1_8_3_,
        technologi2_.ability_id as ability_4_8_3_,
        technologi2_.image as image2_8_3_,
        technologi2_.name as name3_8_3_ 
    from
        ability ability0_ 
    left outer join
        subject subject1_ 
            on ability0_.subject_id=subject1_.id 
    left outer join
        technology technologi2_ 
            on ability0_.id=technologi2_.ability_id 
    where
        ability0_.id=?
Hibernate: 
    select
        abilities0_.subject_id as subject_5_0_0_,
        abilities0_.id as id1_0_0_,
        abilities0_.id as id1_0_1_,
        abilities0_.color as color2_0_1_,
        abilities0_.image as image3_0_1_,
        abilities0_.name as name4_0_1_,
        abilities0_.subject_id as subject_5_0_1_ 
    from
        ability abilities0_ 
    where
        abilities0_.subject_id=?
Hibernate: 
    select
        technologi0_.ability_id as ability_4_8_0_,
        technologi0_.id as id1_8_0_,
        technologi0_.id as id1_8_1_,
        technologi0_.ability_id as ability_4_8_1_,
        technologi0_.image as image2_8_1_,
        technologi0_.name as name3_8_1_ 
    from
        technology technologi0_ 
    where
        technologi0_.ability_id=?

感谢您提前帮忙。

- Ombrelin

1

所以，只是为了确保：您运行生产代码，等待事务提交，然后检查实体是否未从数据存储中删除？ - crizzis

1

可能是某个外键约束失败了，导致操作未能完成。请检查您的应用程序日志。 - Panagiotis Bougioukos

1

@Boug 我的日志中没有错误。事实上，我记录了Hibernate的SQL，也没有执行“DELETE”命令。 - Ombrelin

在调用 deleteById() 方法之前，你能否通过 System.out.println 检查它是否使用了正确的参数？ - Panagiotis Bougioukos

1

我刚刚做了，它们是正确的，并且与我在数据库中的内容相对应。 - Ombrelin

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1个回答

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可以查看英文原文，
原文链接

- Akif Hadziabdic · Accepted Answer

"问题"在于你的映射方式。你的集合是急切地检索。那么为什么会有问题呢？Spring Data JPA中的deleteById首先进行findById操作，在你的情况下，这会急切地加载关联实体。

现在尝试删除实体，但由于它仍然被附加和被另一个实体引用，因此它将被再次持久化，因此删除操作被取消。

可能的解决方案：

使用查询进行删除，并编写自己的查询方法
将关联的一侧标记为lazy

示例：

@Entity
public class Ability {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;
    private String name;
    private String color;
    private String image;

    @ManyToOne(
            fetch = FetchType.LAZY
    )
    private Subject subject;

    @OneToMany(
            mappedBy = "ability",
            cascade = CascadeType.ALL,
            orphanRemoval = true,
            fetch = FetchType.LAZY
    )
    private Set<Technology> technologies;
}

@Repository
public interface AbilityRepository extends CrudRepository<Ability, Integer> {
}

控制器：

abilityRepository.deleteById(abilityId);