Question

这是实体的简化版本，我只显示相关部分。

    @Entity
    @Data
    public class Wrapper {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id

        @OneToOne(mappedBy = "wrapper", cascade = CascadeType.ALL, fetch = FetchType.EAGER, orphanRemoval = true)
        private Application application;

        public Wrapper(Application application) {
            this.application = application;
            application.setWrapper(this);
        }
    }

    @Data
    @Entity
    @EqualsAndHashCode(exclude = "wrapper")
    public class Application {
        @Id
        private Integer id;

        @JsonIgnore
        @OneToOne
        @JoinColumn(name = "id")
        @MapsId
        private Wrapper wrapper;

        @OneToMany(mappedBy = "application", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
        @SortNatural
        private SortedSet<Apartement> ownedApartements = new TreeSet<>();
    }

    @Entity
    @Data
    public class Apartement {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id;

        @ManyToOne(fetch = FetchType.LAZY, optional = false)
        @JoinColumn(name = "application_id", insertable = false, updatable = false)
        private Application application;
    }

@Repository
public interface WrapperRepository extends JpaRepository<Wrapper, Integer> {
}

以上实体生成以下创建表语句：

create table Wrapper (
       id int identity not null,
        primary key (id)
    )

create table Application (
       id int not null,
        primary key (id)
    )

    create table Apartement (
       id int identity not null,
        application_id int not null,
        primary key (id)
    )

     alter table Apartement 
       add constraint FKsrweh1i1p29mdjfp03or318od 
       foreign key (application_id) 
       references Application

       alter table Application
       add constraint FKgn7j3pircupa2rbqn8yte6kyc 
       foreign key (id) 
       references Wrapper

给出以下实体和以下代码：

Apartement apartement1 = new Apartement()
Apartement apartement2 = new Apartement()

Wrapper wrapper = new Wrapper(new Application());

Application application = wrapper.getApplication();
application.getOwnedApartements().addAll(Arrays.asList(apartement1, apartement2));
apartement1.setApplication(application);
apartement2.setApplication(application);

WrapperRepository.saveAndFlush(wrapper);

我在日志中看到三个插入。首先是包装器，然后是应用程序，最后是分割器。但是由于某种原因，第一次保存时application_id为null。但我知道它有双向关系。

我得到的错误是：

Caused by: org.h2.jdbc.JdbcSQLException: NULL not allowed for column "APPLICATION_ID"; SQL statement:
insert into Apartement (id) values (null) [23502-197]

为什么会这样？我需要以正确的顺序存储所有内容吗？我是否需要先存储包装程序和应用程序，然后在拥有应用程序ID后最后存储分割？不能一次休眠存储所有三个吗？还是自己解决这个问题？

Answer 1

对不起，我修复了。

问题是

@ManyToOne(fetch = FetchType.LAZY, optional = false)
        @JoinColumn(name = "application_id", insertable = false, updatable = false)
        private Application application;

我删除了insertable = false，可更新= false并添加了optional = false

那行得通

@JoinColumn(name = "application_id", = false)

Answer 2

尝试一下：

Apartement apartement1 = new Apartement()
Apartement apartement2 = new Apartement()

Wrapper wrapper = new Wrapper(new Application());

Application application = wrapper.getApplication();
application.getOwnedApartements().addAll(Arrays.asList(apartement1, apartement2));
apartement1.setApplicationId(application.getId());
apartement2.setApplicationId(application.getId());

WrapperRepository.saveAndFlush(wrapper);

双向OneToMany和ManyToOne在保存时返回“列不允许使用NULL”

2 个答案: