Java JPA 一起保存主外键
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JPA saving primary and foreign key together
提问by Spark-Beginner
I have two Entities DealEntityand DealTypeEntityand they are related as-
我有两个实体DealEntity和DealTypeEntity与它们相关的原样
@Entity
class DealEntity{
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "DEAL_TYPE_ID")
private DealTypeEntity dealTypeEntity;
}
I am trying to save by creating instance of DealEntity which contains DealTypeEntity ref.
我试图通过创建包含 DealTypeEntity ref 的 DealEntity 实例来保存。
I am using JPA and it giving me exception in entityManager.persist(entity)
我正在使用 JPA，它给了我例外 entityManager.persist(entity)
Oct 17, 2013 3:36:34 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [dispatcherServlet] in context with path [/Travel-Portal] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessApiUsageException:org.hibernate.TransientPropertyV alueException: object references an unsaved transient instance - save the transient instance before flushing: training.impetus.tp.model.DealEntity.dealTypeEntity -> training.impetus.tp.model.DealTypeEntity; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing: training.impetus.tp.model.DealEntity.dealTypeEntity -> training.impetus.tp.model.DealTypeEntity] with root cause
org.hibernate.TransientPropertyValueException: object references an unsaved transient i nstance - save the transient instance before flushing: training.impetus.tp.model.DealEntity.dealTypeEntity -> training.impetus.tp.model.DealTypeEntity
at org.hibernate.engine.spi.CascadingAction.noCascade(CascadingAction.java:380)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:176)
at o rg.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEv entListener.java:160)
at o rg.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlus hingEventListener.java:151)
at o rg.hiborg.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:151)
at org.hib
采纳答案by SubOptimal
Either you do what the error message propose "save the transient instance before flushing"
要么按照错误消息的建议“在刷新前保存瞬态实例”
entityManager.persist(dealTypeEntity);
entityManager.persist(dealEntity);
or you could change the annotation in DealEntity to
或者您可以将 DealEntity 中的注释更改为
@ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.PERSIST)
// then persisting DealEntity would persist the childs also
entityManager.persist(dealEntity);
回答by Lyju I Edwinson
There is another scenario where we can get the same error,
We had this same issue when we manually inserted an entry with update_count column as null value. So we had a member table that relates to fund table. We inserted a new fund manually and forgot to put a value for update_count. When the application created a member with this fund we got this exception while saving the member data org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing:. We are using update_count column for version control [@version].
在另一种情况下，我们可能会遇到相同的错误，当我们手动插入一个带有 update_count 列的条目为空值时，我们遇到了同样的问题。所以我们有一个与基金表相关的成员表。我们手动插入了一个新基金，但忘记为 update_count 设置一个值。当应用程序用这个基金创建一个成员时，我们在保存成员数据时遇到了这个异常org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing:。我们正在使用 update_count 列进行版本控制 [@version]。
回答by Jayen Chondigara
instead of passing reference object passed the saved object, below is explanation which solve my issue,
而不是传递引用对象传递保存的对象，下面是解决我的问题的解释，
//wrong
//错误的
entityManager.persist(dealTypeEntity);
entityManager.persist(dealTypeEntity);
dealEntity.setDealType(dealTypeEntity);
dealEntity.setDealType(dealTypeEntity);
entityManager.persist(dealEntity)
entityManager.persist(dealEntity)
//right
//对
DealTypeEntity savedEntity= entityManager.persist(dealTypeEntity);
DealTypeEntity savedEntity= entityManager.persist(dealTypeEntity);
dealEntity.setDealType(savedEntity);
dealEntity.setDealType(savedEntity);
entityManager.persist(dealEntity)
entityManager.persist(dealEntity)
