Hibernate @非键列的OneToOne映射
我正在为现有的遗留模式使用Hibernate(我无法更新它),有一个奇怪的情况: 表格用户:Hibernate @非键列的OneToOne映射,hibernate,spring-data-jpa,spring-data,hibernate-mapping,Hibernate,Spring Data Jpa,Spring Data,Hibernate Mapping,我正在为现有的遗留模式使用Hibernate(我无法更新它),有一个奇怪的情况: 表格用户: db_id PK 用户id(唯一约束) 。。。其他栏目 表地址 db_id PK 用户id(唯一约束) 。。。常用地址列 这是一对一的关系。我正在创建以下@Entity注释类 class UserEntity { @Id @GeneratedValue private UUID dbId; private String userId; @OneToOne(ca
@Entity
注释类
class UserEntity {
@Id
@GeneratedValue
private UUID dbId;
private String userId;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "user_id", referencedColumnName = "user_id")
private AddressEntity address;
}
Hibernate认为这是一个重复的列定义,这是合理的。但是,由于在地址表中,我没有用户id作为FK或PK,因此我不确定如何将其与Hibernate通信。我试图寻找一个类似的,但没有成功,所以任何建议都将不胜感激。更新
可能有更好的方法来实现这一点,比如使用@naturaid
,但我无法让它与Hibernate 5.2.12.Final一起工作
然而,@JoinFormula
要拯救:
@Entity
@Table(name = "T_USER")
public class UserEntity implements Serializable
{
private static final long serialVersionUID = 1L;
@Id
@Type(type = "uuid-char")
@Column(name = "DB_ID", length = 36)
private UUID dbId;
@Column(name = "USER_ID", nullable = false, unique = true)
private String userId;
@ManyToOne(fetch = FetchType.LAZY)
@JoinFormula("(select x.DB_ID from T_ADDRESS x where x.USER_ID=USER_ID)")
private AddressEntity address;
@Override
public String toString()
{
return String.format("%s: dbId=%s, userId=%s, address=%s",
getClass().getSimpleName(),
dbId,
userId,
address != null ? address.getDbId() : null);
}
}
@Entity
@Table(name = "T_ADDRESS")
public class AddressEntity implements Serializable
{
private static final long serialVersionUID = 1L;
@Id
@Type(type = "uuid-char")
@Column(name = "DB_ID", length = 36, nullable = false, unique = true)
private UUID dbId;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "USER_ID", referencedColumnName = "USER_ID")
private UserEntity user;
@Override
public String toString()
{
return String.format("%s: dbId=%s, user=%s",
getClass().getSimpleName(),
dbId,
user != null ? user.getDbId() : null);
}
}
使用MySQL8测试它,使用:
CREATE TABLE `t_user` (
`DB_ID` varchar(36) NOT NULL,
`USER_ID` varchar(255) NOT NULL,
PRIMARY KEY (`DB_ID`),
UNIQUE KEY `UK_kvueux8cmkdekeqhrs7pumkwi` (`USER_ID`)
) ENGINE=InnoDB
CREATE TABLE `t_address` (
`DB_ID` varchar(36) NOT NULL,
`USER_ID` varchar(255) DEFAULT NULL,
PRIMARY KEY (`DB_ID`),
KEY `FK1s9gxk3we3yq11hjw5hp7ahp5` (`USER_ID`),
CONSTRAINT `FK1s9gxk3we3yq11hjw5hp7ahp5` FOREIGN KEY (`USER_ID`) REFERENCES `t_user` (`user_id`)
) ENGINE=InnoDB
使用这个快速的脏发射器:
public class Main
{
public static void main(String[] args)
{
EntityManagerFactory emf = Persistence.createEntityManagerFactory("test_hibernate");
try
{
EntityManager em = emf.createEntityManager();
try
{
EntityTransaction transaction = em.getTransaction();
transaction.begin();
try
{
UserEntity user = new UserEntity();
user.setDbId(UUID.randomUUID());
user.setUserId("user_" + System.nanoTime());
em.persist(user);
AddressEntity address = new AddressEntity();
address.setDbId(UUID.randomUUID());
address.setUser(user);
user.setAddress(address);
em.persist(address);
transaction.commit();
System.out.println("persisted user: " + user);
System.out.println("persisted address: " + address);
}
catch(Exception e)
{
e.printStackTrace();
transaction.rollback();
}
}
finally
{
em.close();
}
EntityManager em2 = emf.createEntityManager();
try
{
List<UserEntity> userList = em2.createQuery("select x from UserEntity x", UserEntity.class).getResultList();
userList.forEach(x -> System.out.println("loaded user: " + x));
List<AddressEntity> addressList = em2.createQuery("select x from AddressEntity x", AddressEntity.class).getResultList();
addressList.forEach(x -> System.out.println("loaded address: " + x));
}
finally
{
em2.close();
}
}
finally
{
emf.close();
}
System.out.println("ok");
}
}
一个关系定义如下:
class UserEntity {
....
@Column(length = 20)
private String userId;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "userId", referencedColumnName = "userId", insertable = false, updatable = false)
private AddressEntity address;
}
class AddressEntity {
....
@Column(length = 20)
private String userId;
.....
}
谢谢,这个不行。在这种情况下,“拥有”一方是不明确的。看起来可能根本不支持(不是很清楚)你是对的,我低估了这种关系不是基于PK的。我认为Hibernate足够聪明,可以通过正确的映射来理解它,但事实并非如此。请查看更新。然而,这是我提出的第一个想法,即使它有效,可能还有更好的解决方案,这只是一个解决办法。谢谢,也许将来会有时间来看看。目前,我将它们作为没有关系的实体保留,只处理代码中必要的“连接”。很可能我会在将来添加FK,并有一个标准映射!谢谢你花时间调查米歇尔。
persisted user: UserEntity: dbId=a22db668-eda0-4de1-83ae-98a7cd8738bd, userId=user_789235935853200, address=c17c0c28-603e-4961-90b0-16232346e47b
persisted address: AddressEntity: dbId=c17c0c28-603e-4961-90b0-16232346e47b, user=a22db668-eda0-4de1-83ae-98a7cd8738bd
loaded user: UserEntity: dbId=a22db668-eda0-4de1-83ae-98a7cd8738bd, userId=user_789235935853200, address=c17c0c28-603e-4961-90b0-16232346e47b
loaded address: AddressEntity: dbId=c17c0c28-603e-4961-90b0-16232346e47b, user=a22db668-eda0-4de1-83ae-98a7cd8738bd
class UserEntity {
....
@Column(length = 20)
private String userId;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "userId", referencedColumnName = "userId", insertable = false, updatable = false)
private AddressEntity address;
}
class AddressEntity {
....
@Column(length = 20)
private String userId;
.....
}