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休眠一对多注释外键null

[英]hibernate one to many annotation foreign key null

原文 2017-07-25 08:07:38 0 1 java/ hibernate/ hibernate-mapping/ hibernate-onetomany

I have two entities LR.java and LI.java . 我有两个实体LR.java和LI.java 。 One request may have more than one items on it. 一个请求可能包含多个项目。

After the execution of this method the lR is always null inside the item table. 执行此方法后，项目表中的lR始终为null。 What I am doing wrong here? 我在这里做错了什么？ Any suggestions 有什么建议么

1 个解决方案

You defined a bidirectional "manytoone" association, so it's develepoer's responsability to keep consistent both sides of the association (that is: loanRequest and loanItems). 您定义了双向“ manytoone”关联，因此，开发者的责任是保持关联双方的一致性（即：loanRequest和loanItems）。

You should set the field loanRequest of the Loanitem entity to point to "right" LoanRequest. 您应该将Loanitem实体的字段loanRequest设置为指向“正确的” LoanRequest。 Do you so in the addLoanItem ? 您是否在addLoanItem中这样做？

Beside, unless you really need to "navigate" from one entity to the other and backward I suggest you to use unidirectional association, they are far more manageable and less prone to errors like this. 另外，除非您真的需要从一个实体“导航”到另一个实体，然后再向后导航，否则我建议您使用单向关联，它们将更易于管理，并且不易出现此类错误。

Anyway, @XtremeBaumer is right, constructor of LoanItem should be empty. 无论如何，@ XtremeBaumer是正确的，LoanItem的构造函数应该为空。

Hibernate多对一更新外键为null - Hibernate Many to one updating foreign key to null

Hibernate 多对一映射集外键 null - Hibernate many-to-one mapping sets foreign key null

Hibernate 保存对象（一对多关系）外键为空 - Hibernate save object (one to many relationship) foreign key is null

休眠-一对多关系-外键始终为“空” - Hibernate - One to many relation - foreign key always “null”

外键更新异常：外键在Hibernate一对多关系中设置为null - Foreign key update anomaly: foreign keys set to null in Hibernate one-to-many relationship

休眠外键一对一null - Hibernate one-to-one null in foreign key

Hibernate 一对一映射，外键为 NULL - Hibernate One To One mapping, Foreign Key is NULL

Hibernate 一对一映射外键 null - Hibernate One to One mapping Foreign Key null

当引用的非外键列是 null 时，Hibernate 使用 null 初始化一对多集 - Hibernate initializes one-to-many set with null when referenced non-foreign key column is null

Hibernate一对多地将外键翻倍 - Hibernate doubles foreign key in one-to-many

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