“用于实体的映射中的重复列”每列只映射一次 [英] "Repeated column in mapping for entity" where each column is only mapped once

问题描述

我有一个hibernate映射文件ParcelServicePresetIds.hbm.xml：

 < hibernate-mapping> 
< class name =de.delife.sql.ParcelServicePresetIdstable =ParcelServicePresetIDsschema =dbocatalog =xxx> 
< id name =idtype =int> 
< column name =ID/> 
< generator class =assigned/> 
< / id> 
 < column name =ItemID/> 
< /多对一> 
< property name =itemIdcolumn =ItemIDtype =java.lang.Integer/> 
< property name =intValuetype =java.lang.Integer> 
< column name =intValue/> 
< / property> 
< / class> 
< / hibernate-mapping> 
  

运行程序时出现错误：

 创建初始SessionFactory failed.org.hibernate.MappingException：实体映射中的重复列：de.sql.ParcelServicePresetIds列：ItemID（应该使用insert =false更新=false）
  

为什么？

我有另一个实体Others.hbm.xml：

 <多对一名称=itemsBaseclass = de.sql.ItemsBasefetch =selectproperty-ref =itemId> 
< column name =ItemIDunique =true/> 
< /多对一> 
< property name =itemIdcolumn =ItemIDtype =java.lang.Integer/> 
  

在这个实体中它正在工作！我不明白！
有人可以解释这个区别吗？

解决方案

您可能不需要在这里使用propertyRef。它可以简单地为：

 <多对一名称=itemsBaseclass =de.sql.ItemsBase fetch =selectcolumn =ItemID/> 
  

另外，您不需要 itemId 。

回答问题的第二部分：

• 无论何时您提供propertyRef，都需要使用属性定义进行跟踪。


• 如果它是'托管列'，例如外键引用，您应该使用 insert =falseupdate =false


• 来限定属性定义。你不需要一个propertyRef。您可以在多对一部分使用简单的列定义。

I have a hibernate mapping file ParcelServicePresetIds.hbm.xml:

<hibernate-mapping>
<class name="de.delife.sql.ParcelServicePresetIds" table="ParcelServicePresetIDs" schema="dbo" catalog="xxx">
    <id name="id" type="int">
        <column name="ID" />
        <generator class="assigned" />
    </id>
    <many-to-one name="itemsBase" class="de.sql.ItemsBase" fetch="select" property-ref="itemId">
        <column name="ItemID" />
    </many-to-one>
    <property name="itemId" column="ItemID" type="java.lang.Integer"/>
    <property name="intValue" type="java.lang.Integer">
        <column name="intValue" />
    </property>
</class>
</hibernate-mapping>

When I run my program I get an error:

Initial SessionFactory creation failed.org.hibernate.MappingException: Repeated column in mapping for entity: de.sql.ParcelServicePresetIds column: ItemID (should be mapped with insert="false" update="false")

Why?

I've another entity Others.hbm.xml:

<many-to-one name="itemsBase" class="de.sql.ItemsBase" fetch="select" property-ref="itemId">
    <column name="ItemID" unique="true" />
</many-to-one>
<property name="itemId" column="ItemID" type="java.lang.Integer"/>

In this entity it's working!!! I do not understand it! Can someone explain the difference?

解决方案

You probably don't need to use a propertyRef here. It could simply be:

<many-to-one name="itemsBase" class="de.sql.ItemsBase" fetch="select" column="ItemID"/>

Also, you don't require the property declaration for itemId.

To answer the second part of the question:

• Whenever you give propertyRef, you need to follow it up with a property definition.
• If it is a 'managed column', i.e. a foreign-key-reference for example; you ought to qualify the property definition with insert="false" update="false"
• However, in most cases; you donot need a propertyRef. You can do with a simple column definition in the many-to-one section.

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