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.
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.
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);
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.
I'm mapping the relationship using @OneToOne
. I've tried several combinations of FetchType
, optional
and @LazyToOne
, but so far without success.
Here is the code for both MyEntity and MyEntityInfo classes (additional getters and setters removed):
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:
@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;
I've tried this solution, but as I said, it didn't work for me:
Hibernate lazy loading for reverse one to one workaround - how does this work?
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: 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;
After following @SternK link, and upgrading to Wildfly 19 and Hibernate 5.4.14, it finally worked by using
@MapsId
.The right mapping to use is this:
MyEntity:
MyEntityInfo: