在具有懒惰行为的PK之间休眠OneToOne [英] Hibernate OneToOne between PK's with lazy behaviour

问题描述

我正在尝试使用Hibernate 5.3.13.Wildfly 18下的注解最终拥有一个名为MyEntity的实体以及另一个名为MyEntityInfo的实体.

I'm trying to achieve to have an entity called MyEntity along with another entity called MyEntityInfo using Hibernate 5.3.13.Final with annotations under Wildfly 18.

这个想法是让MyEntity存储一些通常要求的字段，而MyEntityInfo存储一些很少要求的字段.两者共享一个相同的主键，称为SID(Long)，并且从Info的SID到Entity的SID都有一个FK.可能有没有信息的实体.

The idea is to have MyEntity store some commonly requested fields, and MyEntityInfo store some rarely requested fields. Both share the same primary key called SID (Long), and there is a FK from Info's SID to Entity's SID. There can be entities without info.

通常，您不需要其他信息.例如，当我查询这样的实体时，我不希望获取信息实体:

Normally you will not require the additional info. For example, I don't want the info entity to be fetched when I query my entity like this:

MyEntityImpl entity = em.find(MyEntityImpl.class, 1L);

但是，当我运行这段代码时，我发现还有第二个查询，沿着主要查询获取Info实体，就像在EAGER行为中一样.

However, when I run this code, I find that there's a second query, fetching the Info entity along the main one, as in an EAGER behaviour.

我正在使用@OneToOne映射关系.我已经尝试了FetchType，optional和@LazyToOne的几种组合，但是到目前为止没有成功.

I'm mapping the relationship using @OneToOne. I've tried several combinations of FetchType, optional and @LazyToOne, but so far without success.

这是MyEntity和MyEntityInfo类的代码(已删除其他getter和setter):

Here is the code for both MyEntity and MyEntityInfo classes (additional getters and setters removed):

MyEntity(ID生成器是自定义序列生成器):

MyEntity (ID generator is a custom sequence generator):

@Entity
@Table(name = MyEntityImpl.TABLE_NAME)
public class MyEntityImpl {

    public static final String TABLE_NAME = "TMP_MY_ENTITY";

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "GEN_" +
            TABLE_NAME)
    @GenericGenerator(name = "GEN_" +
            TABLE_NAME, strategy = CoreIdGenerator.ID_GENERATOR, parameters = {
                    @Parameter(name = "tableName", value = TABLE_NAME) })
    @Column(name = "sid", nullable = false, unique = true)
    private Long               sid;

    @OneToOne(mappedBy = "myEntity", cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = true)
    @LazyToOne(LazyToOneOption.NO_PROXY)
    private MyEntityInfoImpl   info;

    @Column
    private String             field;

MyEntityInfo:

MyEntityInfo:

@Entity
@Table(name = MyEntityInfoImpl.TABLE_NAME)
public class MyEntityInfoImpl {
    public static final String TABLE_NAME = "TMP_MY_ENTITY_INFO";

    @Id
    @Column(name = "SID", nullable = false, unique = true)
    private Long               sid;

    @OneToOne(fetch = FetchType.EAGER, optional = false)
    @JoinColumn(name = "SID", referencedColumnName = "SID", insertable = false, updatable = false, nullable = false)
    private MyEntityImpl       myEntity;

    @Column(name = "INFO_FIELD")
    private String             infoField;

我已经尝试过此解决方案，但正如我所说，它对我不起作用:

I've tried this solution, but as I said, it didn't work for me:

休眠延迟加载一对一的解决方法-如何运作?

我已经设法使用@OneToMany和手动管理数据来做一些类似的事情，但这不是我想要做的.但是，也欢迎使用@OneToOne是否可以实现此目标的另一种替代方法和信息，或执行此操作的正确设计模式.

I've managed to do something somewhat similar using @OneToMany and managing data manually, but that's not what I'd like to do. However, another alternatives and information on whether this can be achieved or not using @OneToOne, or the right design pattern to do this are also welcome.

PS:为SQL Server创建数据库表，以备您尝试:

PS: Database tables creation for SQL Server, in case you want to try it:

create table TMP_MY_ENTITY (SID NUMERIC(19,0) NOT NULL, FIELD VARCHAR(100));
go
ALTER TABLE TMP_MY_ENTITY ADD CONSTRAINT PK_TMP_MY_ENTITY PRIMARY KEY CLUSTERED (SID);
go

create table TMP_MY_ENTITY_INFO (SID NUMERIC(19,0) NOT NULL, INFO_FIELD VARCHAR(100));
go
ALTER TABLE TMP_MY_ENTITY_INFO ADD CONSTRAINT PK_TMP_MY_ENTITY_INFO PRIMARY KEY CLUSTERED (SID);
go

CREATE SEQUENCE SEQ_TMP_MY_ENTITY START WITH 1 INCREMENT BY 1 MINVALUE 1 CACHE 20;

alter table TMP_MY_ENTITY_INFO add constraint FK_TMP_MY_ENT_INFO_MY_ENT FOREIGN KEY (SID) references TMP_MY_ENTITY(SID);
go

insert into TMP_MY_ENTITY(SID, FIELD) VALUES (NEXT VALUE FOR SEQ_TMP_MY_ENTITY, 'Field 1');
insert into TMP_MY_ENTITY_INFO(SID, INFO_FIELD) VALUES ((SELECT MAX(SID) FROM TMP_MY_ENTITY), 'Info 1');

insert into TMP_MY_ENTITY(SID, FIELD) VALUES (NEXT VALUE FOR SEQ_TMP_MY_ENTITY, 'Field 2');
insert into TMP_MY_ENTITY_INFO(SID, INFO_FIELD) VALUES ((SELECT MAX(SID) FROM TMP_MY_ENTITY), 'Info 2');

insert into TMP_MY_ENTITY(SID, FIELD) VALUES (NEXT VALUE FOR SEQ_TMP_MY_ENTITY, 'Field 3 no info');

-- DELETE ALL

drop table TMP_MY_ENTITY_INFO;
drop table TMP_MY_ENTITY;
drop sequence SEQ_TMP_MY_ENTITY;

推荐答案

在跟随@SternK链接并升级到Wildfly 19和Hibernate 5.4.14之后，它终于可以使用@MapsId了.

After following @SternK link, and upgrading to Wildfly 19 and Hibernate 5.4.14, it finally worked by using @MapsId.

要使用的正确映射是这样:

The right mapping to use is this:

MyEntity:

public class MyEntityImpl {

    @OneToOne(mappedBy = "myEntity", cascade = CascadeType.REMOVE, fetch = FetchType.LAZY, optional = true)
    @JoinColumn(name = "SID")
    private MyEntityInfoImpl   info;

MyEntityInfo:

MyEntityInfo:

public class MyEntityInfoImpl {

    @OneToOne(fetch = FetchType.EAGER, optional = false)
    @MapsId
    @JoinColumn(name = "SID", referencedColumnName = "SID", insertable = false, updatable = false, nullable = false)
    private MyEntityImpl       myEntity;

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