Database 为什么Hibernate会为@JoinTable的双向@OneToMany关系生成一个复杂的子查询

我正在使用Spring Boot和Hibernate，通过中间表管理具有双向@OneToMany关系的实体.以下是我的实体定义:

@Entity
@Table(name = "feedback")
@NamedEntityGraph(name = "full", includeAllAttributes = true)
@Getter
@Setter
@SequenceGenerator(allocationSize = 1, name = "feedback_seq_gen", sequenceName = "feedback_seq")
public class Feedback {

    @Id
    @Column(name = "id", nullable = false)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "feedback_seq_gen")
    private Long id;

    @Column(name = "text", length = Integer.MAX_VALUE)
    private String text;

    @OneToMany(mappedBy = "feedback", fetch = FetchType.LAZY)
    private Set<Image> images = new HashSet<>();
}

@Entity
@Table(name = "image")
@Getter
@Setter
@SequenceGenerator(allocationSize = 1, name = "image_seq_gen", sequenceName = "image_seq")
public class Image {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "image_seq_gen")
    @Column(name = "id", nullable = false)
    private Long id;

    @Column(name = "url", length = Integer.MAX_VALUE)
    private String url;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinTable(name = "feedback_image",
            inverseJoinColumns = @JoinColumn(name = "feedback_id"),
            joinColumns = @JoinColumn(name = "image_id"))
    private Feedback feedback;

    public void setFeedback(Feedback feedback) {
        feedback.getImages().add(this);
        this.feedback = feedback;
    }
}

Feedback和Image实体通过使用名为feedback_image的@JoinTable的@OneToMany关系进行关联.我使用连接表的原因是因为我需要在创建反馈之前上传图像.

存储库:

public interface FeedbackRepository extends JpaRepository<Feedback, Long> {

    @EntityGraph("full")
    @Query("select f from Feedback f where f.id = :id")
    Optional<Feedback> getFullFeedbackById(Long id);
}

在测试关系和获取逻辑时，Hibernate会生成一个复杂的SQL查询，其中包括对子查询的附加联接:

SELECT f1_0.id, i1_0.feedback_id, i1_1.id, i1_1.url, f1_0.text
FROM feedback f1_0
         LEFT JOIN feedback_image i1_0 ON f1_0.id = i1_0.feedback_id
         LEFT JOIN (image i1_1 LEFT JOIN feedback_image i1_2 ON i1_1.id = i1_2.image_id) ON i1_1.id = i1_0.image_id
WHERE f1_0.id = ?;

然而，我注意到，如果我将关系切换到@ManyToMany，Hibernate会生成一个更简单、更直接的查询:

SELECT f1_0.id, i1_0.feedback_id, i1_1.id, i1_1.url, f1_0.text
FROM feedback f1_0
         LEFT JOIN feedback_image i1_0 ON f1_0.id = i1_0.feedback_id
         LEFT JOIN image i1_1 ON i1_1.id = i1_0.image_id
WHERE f1_0.id = ?;

但这种方法与我的概念模型不一致.

因此，我的问题是:Hibernate为该设置生成的附加连接子查询正常吗？如果是，为什么会发生这种情况？