我有两个表:UserExtended
继承自User
. 但我不能将现有User
的提升到UserExtended
.
实体:
@Entity
@Table
@Inheritance(strategy = InheritanceType.JOINED)
public class User {
// columns: id, email, etc.
}
@Entity
@Table
@PrimaryKeyJoinColumn(name = "id", referencedColumnName = "id")
public class UserExtended extends User {
// columns
}
服务:
// Repositories
@Autowired
private UserDao userDao;
@Autowired
private UserExtendedDao userExtendedDao;
public void promoteUser() {
User user = userDao.getUserByEmail(email);
UserExtended userExt;
if (user != null) {
if (user instanceof UserExtended) {
// cast UserExtended
userExt = (UserExtended) user;
} else {
// extend User to UserExtended
userExt = new UserExtended();
userExt.setId(user.getId());
// userExt.setEmail(user.getEmail());
userExt = userExtendedDao.save(userExt); // exception here!
}
} else {
// create new UserExtended
}
}
使用此代码,我得到异常:SQLServerException: Cannot insert the value NULL into column 'email', table 'User'; column does not allow nulls. INSERT fails
因为email
DB 中的列不为空。
当我取消注释该行时userExt.setEmail(user.getEmail());
,我得到另一个异常SQLServerException: Cannot insert duplicate key row in object 'User' with unique index 'UQ_User_email'. The duplicate key value is (xxx@mail.com)
,因为email
应该是唯一的。
我可以使用普通 SQL 进行插入,INSERT INTO UserExtended (id) VALUES (13);
我如何使用 Hibernate 和 Spring Data JPA 来做同样的事情?