Spring 数据 JPA - ManyToOne 无法在不修改 parent 列表的情况下删除 child

Question

我与以下问题斗争了一个星期：

如何在不修改关系的拥有 (parent) 端的列表的情况下通过存储库删除 child 实体？

提前致谢。

我希望得到一些答案！

childclass:

@Entity
@Table(name = "child")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class Child implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
    @SequenceGenerator(name = "sequenceGenerator")
    private Long id;

    @ManyToOne
    private Parent parent;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Long getParent() {
        return parent;
    }

    public void setParent(Parent parent) {
        this.parent = parent;
    }
}

还有 parent class:

@Entity
@Table(name = "parent")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class Parent implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
    @SequenceGenerator(name = "sequenceGenerator")
    private Long id;

    @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonIgnore
    @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
    private Set<Child> children = new HashSet<>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Set<Child> getChildren() {
        return children;
    }

    public void setChildren(Set<Child> children) {
         this.children = children;
    }

    public Parent addChild(Child child) {
        this.children.add(child);
        child.setParent(this);
        return this;
    }

    public Parent removeChild(Child child) {
        this.children.remove(child);
        child.setParent(null);
        return this;
    }
}

这里是测试:

@Test
@Transactional
public void testParentToChildRelationShip() {
    Parent parent = new Parent();
    Child child = new Child();

    parent.addChild(child);
    parent.addChild(new Child());
    parent.addChild(new Child());
    parent.addChild(new Child());

    parentRepository.save(parent);

    Assertions.assertThat(parentRepository.count()).isEqualTo(1L);
    Assertions.assertThat(childRepository.count()).isEqualTo(4L);

    childRepository.delete(child);


    Assertions.assertThat(parentRepository.count()).isEqualTo(1L);
    // fails
    Assertions.assertThat(childRepository.count()).isEqualTo(3L);

    parentRepository.delete(parent.getId());

    Assertions.assertThat(parentRepository.count()).isEqualTo(0L);
    Assertions.assertThat(childRepository.count()).isEqualTo(0L);
}

如果我在删除 child、

之前插入，测试将有效

child.getParent().removeChild(child);

但我想避免这样调用。有没有办法让它只调用 Child-JPA-Repository.delete 方法就可以工作？或者我错过的其他注释？

Answer 1

由于 child 与 parent 有关联，您正面临此问题，您需要使用

删除子项和父项之间的 link

parent.removeChild(child);

或

child.getParent().removeChild(child);

Answer 2

从 parent class 以及 children

的 setter 和 getter 中删除这些行

@OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true)
        @JsonIgnore
        @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
        private Set<Child> children = new HashSet<>();

我认为您可以从 parent class 中删除 child mapping，这样您就可以使用 ChildRepository delete() 方法轻松删除 child 行，但问题是您必须使用 ChildRepository save() 保存您的 child manually。您不能使用 ParentRepository 保存 child object 和 parent object。像下面这样更改您的 Test 代码以保存 child 和 parent

Parent parent = new Parent();
Parent parent = parentRepository.save(parent);

    Child child = new Child();
    child.setParent(parent);
    childRepository.save(child);

Spring 数据 JPA - ManyToOne 无法在不修改 parent 列表的情况下删除 child

Spring Data JPA - ManyToOne unable to delete child without modifying parent list

spring

hibernate

jpa

spring-data-jpa

many-to-one