Hibernate 序列为每个子插入递增父 ID答案

【问题标题】：Hibernate sequence increments parent id for each child insertHibernate 序列为每个子插入递增父 ID
【发布时间】：2022-09-27 17:16:48
【问题描述】：

使用休眠，插入到子级失败，并在子级上出现“参照完整性约束违规”。每个孩子的父 ID 都会递增。

// Parent: Composite primary key, one auto generated
@IdClass(PlanId.class)
public class PlanEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = \"PlanIdGenerator\")
    @SequenceGenerator(name = \"PlanIdGenerator\", sequenceName = \"PLAN_ID_SEQUENCE\", allocationSize = 1)
    private Long id;

    @Id
    private Long version;

    @OneToMany(cascade = CascadeType.ALL, mappedBy = \"planEntity\", fetch = FetchType.LAZY, orphanRemoval = true) //
    private Collection<PlanGoalBucketEntity> goalBuckets = new ArrayList<>();

public void addPlanGoalBucketEntity(PlanGoalBucketEntity goalBucket) {
    goalBuckets.add(goalBucket);
    goalBucket.setPlanEntity(this);
}

public void removePosition(PlanGoalBucketEntity goalBucket) {
    goalBuckets.remove(goalBucket);
    goalBucket.setPlanEntity(null);
}
.....    
}

//Child

public class PlanGoalBucketEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne(optional = false)
    @JoinColumns({ @JoinColumn(name = \"plan_id\", referencedColumnName = \"id\"),
            @JoinColumn(name = \"version\", referencedColumnName = \"version\") })
    private PlanEntity planEntity;

    .....
}

用一个 PlanGoalBucketEntity（子）插入到平面（父）就可以了。

插入具有多个子项的父项，它会因外键违规“参照完整性约束违规”而失败。插入第一个孩子很好，但第二个孩子失败了，因为它增加了第二个孩子的父 ID。

无法弄清楚出了什么问题。

标签： java spring-boot hibernate spring-data-jpa

【解决方案1】：

你还没有粘贴你的 PlanId 类，但我认为它是这样的

public class PlanId implements Serializable {

    public Long id;
    public Long version;
}

我复制了您的代码并进行了以下测试，我所做的只是如上所述实现 PlanId 并在您的实体中添加了必要的设置器。我正在使用 H2 DB

    @Test
    public void plan() {
        PlanEntity planEntity = new PlanEntity();
        planEntity.setVersion(1L);

        planEntity.addPlanGoalBucketEntity(new PlanGoalBucketEntity());
        planEntity.addPlanGoalBucketEntity(new PlanGoalBucketEntity());

        entityManager.getTransaction().begin();
        entityManager.persist(planEntity);
        entityManager.getTransaction().commit();

        // Check save of 2 plan goal buckets is successful

        List<PlanEntity> planEntities =
                entityManager.createQuery(
                        "select distinct p from PlanEntity p left join fetch p.goalBuckets", PlanEntity.class)
                        .getResultList();

        assertEquals(1, planEntities.size());
        assertEquals(2, planEntities.iterator().next().getGoalBuckets().size());
    }

【讨论】：