问题描述
我正在将我的应用程序从基于xml的映射迁移到基于JPA注解的映射。但是这只会在一个简单的情况下失败。例如，我有以下3个实体：
@Entitiy
public class UserAccount {
@OneToMany（cascade = CascadeType.ALL，orphanRemoval = true）
@JoinColumn（name =user_account_id，nullable = false，
insertable = true，updatable = false）
@ NotNull
私人设置< Authority>当局;
@OneToOne（cascade = CascadeType.ALL）
@JoinColumn（name =USER_ID，nullable = false）
... get和setter
@Entity
公共类授权{
@Column
私有字符串权限;
... get和setter
}
@实体
公共类用户{
...一些属性
}
如果我创建一个新的UserAccount实例并尝试保存它，我得到一个异常，因为权限实例没有保存，这意味着它不像它应该做的那样级联。
org.springframework.dao .InvalidDataAccessApiUsageException：
org.hibernate.TransientObjectException：对象引用一个未保存的瞬态
实例 - 在冲洗前保存瞬态实例：Authority ...
发生这种情况是因为hibernate尝试更新权限行（以前没有插入）：
<$ p $ h
Hibernate：
插入user_accounts ...
Hibernate：
更新权限设置user_account_id =？其中id =？
我使用以下服务保存UserAccount实例。
@Service
public class UserAccountService {
@Resource
private UserAccountRepository userAccountRepository;
@Transactional（propagation = Propagation.REQUIRED，readOnly = false）
public void save（UserAccount userAccount）{
userAccountRepository.save（userAccount）;
奇怪的是，用户实例将被保存，所以OneToOne映射级联（如果我删除了UserAccount.authorities属性）。但是，这与基于xml的映射（并且没有JPA）一起工作。我最终调用了一个单独的方法来存储Authoriy实例。
@Service
public class UserAccountService {
@Resource
private UserAccountRepository userAccountRepository;
@Resource
private AuthorityRepository authorityRepository;
@Transactional（propagation = Propagation.REQUIRED，readOnly = false）
public void save（UserAccount userAccount）{
userAccountRepository.save（userAccount）;
authorityRepository.save（userAccount.getAuthoritiesSet（））;
}
}
这意味着，我手动级联。但是，查看执行的SQL语句，我可以看到，hibernate插入了权限实例，之后，它更新此行以设置UserAccount引用：
<$ p $ b $ Hibernate：
插入用户...
Hibernate：
插入user_accounts ...
Hibernate ：
插入权限（权限）值（？）
Hibernate：
更新权限集user_account_id =？其中id =？
对于我来说这是一个性能问题，因为有很多权限，我不想拥有20次插入，之后20次更新。但我无法删除更新，并告诉hibernate将user_account_id与权限一起设置。
因为我还有许多其他有OneToMany关系的对象，所以我我对解决这个问题非常感兴趣，并感谢您的帮助和想法。
Hibernate：4.3.4.Final，
spring data jpa：1.5.1.RELEASE
祝好，
Daniel
我与ManyToOne映射有类似的问题。
通过向版本字段添加默认值解决了问题。
@Version
@Column（name = VERSION）
private Integer version = 1;
I am migrating my app from xml based mapping to JPA annotation based mapping. But this fails only in a simple case. For example, I've the following 3 entities:
@Entitiy
public class UserAccount {
@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "user_account_id", nullable = false,
insertable = true, updatable = false)
@NotNull
private Set<Authority> authorities;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name="USER_ID", nullable = false)
... get and setter
}
@Entity
public class Authority {
@Column
private String authority;
... get and setter
}
@Entity
public class User {
... some properties
}
If I create a new UserAccount instance and try to save it, I got an exception, because the Authority instance wasn't saved, which means, it doesn't cascade as it supposed to do.
org.springframework.dao.InvalidDataAccessApiUsageException:
org.hibernate.TransientObjectException: object references an unsaved transient
instance - save the transient instance before flushing: Authority ...
This happens, because hibernate tries to update the authority row (which wasn't inserted before):
Hibernate:
insert into users ...
Hibernate:
insert into user_accounts ...
Hibernate:
update authorities set user_account_id=? where id=?
I used the following service to save the UserAccount instance.
@Service
public class UserAccountService {
@Resource
private UserAccountRepository userAccountRepository;
@Transactional(propagation = Propagation.REQUIRED, readOnly = false)
public void save(UserAccount userAccount) {
userAccountRepository.save(userAccount);
}
}
The strange thing is, that the User instance will be saved, so the OneToOne mapping cascades (if I remove the UserAccount.authorities property). But this worked with the xml based mapping (and without JPA). I ended up in calling a separate method to store the Authoriy instances.
@Service
public class UserAccountService {
@Resource
private UserAccountRepository userAccountRepository;
@Resource
private AuthorityRepository authorityRepository;
@Transactional(propagation = Propagation.REQUIRED, readOnly = false)
public void save(UserAccount userAccount) {
userAccountRepository.save(userAccount);
authorityRepository.save(userAccount.getAuthoritiesSet());
}
}
Which means, I cascade manually... However, looking into the executed SQL statements, I can see, that hibernate inserts the authority instance and after that, it updates this row to set the UserAccount reference:
Hibernate:
insert into users ...
Hibernate:
insert into user_accounts ...
Hibernate:
insert into authorities (authority) values (?)
Hibernate:
update authorities set user_account_id=? where id=?
And for me this is a performance issue, because there are many authorities and I do not want to have 20 inserts and after that 20 updates. But I was not able to "remove" the updates and tell hibernate to set the user_account_id together with the authority.
Because I've many other objects having OneToMany relations, I am very interested in resolving this problem and appreciate your help and thoughts.
Hibernate: 4.3.4.Final,spring data jpa: 1.5.1.RELEASE
Best regards,Daniel
I had very similar issue with ManyToOne mapping.Solved problem by adding default value to version field.
@Version
@Column(name = "VERSION")
private Integer version = 1;
这篇关于@OneToMany JPA注释导致不必要的sql更新，不会级联的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！