本文介绍了Nhibernate 3中的一对一映射的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有以下课程
namespace Extractor.Mapping
{
public class Application
{
public virtual Guid Id { get; set; }
public virtual string intId { get; set; }
virtual SQuery sQuery { get; set; }
}
}
namespace Extractor.Mapping
{
public class SQuery
{
public virtual int Id { get;set; }
public virtual Guid Application { get;set; }
public virtual string Type { get;set; }
}
}
SQuery和Application之间的关系是SQuery中名为"Application"的FK
The relation between SQuery and Application is the FK in SQuery named "Application"
这些是de hbm文件
these are de hbm files
Application.hbm.xml
Application.hbm.xml
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Extractor"
namespace="Extractor.Mapping">
<class name="Application" >
<id name="Id" column="Id">
<generator class="assigned"/>
</id>
<property name = "intId" column = "IntId" type = "string"/>
<one-to-one name="sQuery" property-ref ="Application" class="SicQuery"/>
</class>
</hibernate-mapping>
<?xml version="1.0" encoding="utf-8" ?>
SQuery.hbm.xml
SQuery.hbm.xml
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="BuroExtractorD"
namespace="BuroExtractorD.Mapping">
<class name="SQuery" >
<id name="Id" column="Id">
<generator class="increment"/>
</id>
<property name="Application" column="Application" type ="Guid"/>
<property name="Type" column="Type" type="string"/>
</class>
</hibernate-mapping>
问题是,当我尝试访问一些SQuery对象的列表时,出现以下异常:
So, the thing is this, when i try to access a list of some SQuery objects, I get the following exception:
NHibernate.PropertyAccessException: Invalid Cast (check your mapping for property type mismatches); setter of Extractor.Mapping.SQuery ---> System.InvalidCastException
我试图像这样到达那里:
I try to get there like this:
ICriteria crit = session.CreateCriteria(typeof(SQuery));
IList<SQuery> list = crit.List<SQuery>();
预先感谢
推荐答案
one-to-one
的点是引用关系.这种映射不能与ValueTypes
有关.
public class Application
{
public virtual SQuery sQuery { get; set; }
...
}
public class SQuery
{
// wrong, Guid is ValueType, not a reference
// public virtual Guid Application { get;set; }
// corrrect - one to one == bi-directional
public virtual Application Application { get;set; }
...
}
映射应如下图所示
<class name="Application" >
...
// class should be SQuery
//<one-to-one name="sQuery" property-ref ="Application" class="SicQuery"/>
<one-to-one name="sQuery" property-ref="Application" class="SQuery"/>
<class name="SQuery" >
...
<many-to-one name="Application" class="Application"
column="Application" unique="true"/>
在此处查看更多信息:
这篇关于Nhibernate 3中的一对一映射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!