我在 Spring Boot 中遇到 Hibernate 问题。
我们有 2 个表,users
和 user_info
,具有零到一(因此可以为空的一对一)关系。
user_info
有一个指向 users.user_id
的主外键:
CREATE TABLE `users` (
`user_id` bigint(20) NOT NULL AUTO_INCREMENT,
`username` varchar(45) NOT NULL,
...
PRIMARY KEY (`user_id`)
)
CREATE TABLE `users_info` (
`user_id` bigint(20) NOT NULL,
`name` varchar(45) NOT NULL,
`surname` varchar(45) NOT NULL,
`mail` varchar(45) DEFAULT NULL,
...
PRIMARY KEY (`user_id`),
KEY `fk_user_id_idx` (`user_id`),
CONSTRAINT `fk_user_id` FOREIGN KEY (`user_id`)
REFERENCES `users` (`user_id`)
ON DELETE NO ACTION ON UPDATE NO ACTION
)
这些是模型:
@Entity
@Table(name = "users")
public class User implements UserDetails, Buildable<User.Builder> {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "user_id")
private Long id;
private String username;
@Nullable
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name="user_id")
@JsonUnwrapped
private UserInfo userInfo;
...
}
@Entity
@Table(name = "users_info")
public class UserInfo {
@Id
@Column(name = "user_id")
private Long id;
@Nullable
private String name;
@Nullable
private String surname;
...
}
当我使用此配置运行 Spring 应用程序时,它会抛出一个错误:
org.hibernate.id.IdentifierGenerationException ids for this class must be manually assigned before calling save()
如果 User 实体不为 null,我们如何级联持久化 UserInfo
实例?
感谢您的回答!
最佳答案
您的映射是向后的。 UserInfo 应引用其所附加的用户,并且是关联的所有者。而且你还应该说,它的ID也是用户的外键。
@Entity
@Table(name = "users")
public class User implements UserDetails, Buildable<User.Builder> {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "user_id")
private Long id;
private String username;
@Nullable
@OneToOne(mappedBy="user", cascade = CascadeType.ALL)
@JsonUnwrapped
private UserInfo userInfo;
...
}
@Entity
@Table(name = "users_info")
public class UserInfo {
@Id
@Column(name = "user_id")
private Long id;
@Nullable
private String name;
@Nullable
private String surname;
@OneToOne
@MapsId
private User user;
...
关于java - Hibernate 零到一单向,具有反向主外键级联,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/44717813/