在我们使用NHibernate进行软件开发的时候,最初的例子会告诉我们用CodeSmith来生成Mapping,但是没有告诉你是按什么规则生成的,在使用的过程中你会发现根据不同的情况会有不同的问题出现。出现这些问题的原因就是CodeSmith中的NHibernate Template生成的代码是按默认的值生成的,当你的系统在全盘不是默认的值的时候就要根据情况做不同的配置。这些都在NHibernate的相应的文档中有提到,只是一不小心就忽略过去了,在网上搜索来的中文的帖子,可读性都很强,但是技术的细节做的不够,总是忽略了初学入门的时候那种懵懵懂懂的状态。既然是我们是为了让别人少走些弯路,那就要做的细些,不要做什么做了一半,觉得这也简单,那也简单,小问题也会影响大结果。所以在写文档的时候,无所不细,无所不到,就当我们什么也不会吧;)
在我们使用NHibernate进行软件开发的时候,最初的例子会告诉我们用CodeSmith来生成Mapping,但是没有告诉你是按什么规则生成的,在使用的过程中你会发现根据不同的情况会有不同的问题出现。出现这些问题的原因就是CodeSmith中的NHibernate Template生成的代码是按默认的值生成的,当你的系统在全盘不是默认的值的时候就要根据情况做不同的配置。这些都在NHibernate的相应的文档中有提到,只是一不小心就忽略过去了,在网上搜索来的中文的帖子,可读性都很强,但是技术的细节做的不够,总是忽略了初学入门的时候那种懵懵懂懂的状态。既然是我们是为了让别人少走些弯路,那就要做的细些,不要做什么做了一半,觉得这也简单,那也简单,小问题也会影响大结果。所以在写文档的时候,无所不细,无所不到,就当我们什么也不会吧;)
现在还是回过头来说CodeSmith生成的代码。如果是你的数据库表格中的定义如下:
字段名 |
类型 |
长度 |
主键 |
空 |
Id |
bigint |
8 |
|
not null |
userid |
char |
10 |
primary key |
not null |
other |
varchar |
50 |
|
not null |
这个表在生成代码的时候会有很多的问题出现,其一会生成两个Id字段,在生成Dll的时候就通不过编译;其二,生成的*.hbm.xml中的Id值亦会有两个,但是关键字的生成也会有问题出现。生成的例子如下:
*.cs
public class Accessory
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedSubBlock.gif)
Member Variables#region Member Variables
protected string _id;
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
protected long _id;
protected string _other;
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
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..
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
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Public Properties#region Public Properties
public virtual string Id
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{return _id;}
set
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
if ( value != null && value.Length > 8)
throw new ArgumentOutOfRangeException("Invalid value for Id", value, value.ToString());
_id = value;
}
}
public virtual long Id
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{ return _id; }
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
set
{ _id = value; }
}
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
public virtual string Other
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{ return _other; }
set
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
if ( value != null && value.Length > 50)
throw new ArgumentOutOfRangeException("Invalid value for Other", value, value.ToString());
_other = value;
}
}
}
*.hbm.xml
<class name="OfficeSystem.Pmis.Entities.Accessory, OfficeSystem.Pmis.Entities" table="Accessories">
<id name="Id" type="String" unsaved-value="null">
<column name="userId" length="8" sql-type="char" not-null="true" unique="true" index="PK_Accessories"/>
<generator class="native" />
</id>
<property name="Id" type="Int64">
<column name="id" length="8" sql-type="bigint" not-null="true"/>
</property>
<property name="Other" type="String">
<column name="other" length="50" sql-type="varchar" not-null="true"/>
</property>
看到了么?有两个同名的Id值存在,在这个时候你就要手动的来改一下这两个文件,将相应的文件改成如下的形式:
*.cs
public class Accessory
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedSubBlock.gif)
Member Variables#region Member Variables
protected string _userId;
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
protected long _id;
protected string _other;
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
![](https://www.cnblogs.com/Images/dot.gif)
![](https://www.cnblogs.com/Images/dot.gif)
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..
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
![](https://www.cnblogs.com/Images/OutliningIndicators/ContractedSubBlock.gif)
Public Properties#region Public Properties
public virtual string UserId
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{return _userId;}
set
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
if ( value != null && value.Length > 8)
throw new ArgumentOutOfRangeException("Invalid value for UserId", value, value.ToString());
_userId = value;
}
}
public virtual long Id
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{ return _id; }
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
set
{ _id = value; }
}
![](https://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif)
public virtual string Other
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
get
{ return _other; }
set
![](https://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
if ( value != null && value.Length > 50)
throw new ArgumentOutOfRangeException("Invalid value for Other", value, value.ToString());
_other = value;
}
}
}
*.hbm.xml
<class name="OfficeSystem.Pmis.Entities.Accessory, OfficeSystem.Pmis.Entities" table="Accessories">
<id name="UserId" type="String" unsaved-value="null">
<column name="userId" length="8" sql-type="char" not-null="true" unique="true" index="PK_Accessories"/>
<generator class="assigned" />
</id>
<property name="Id" type="Int64">
<column name="id" length="8" sql-type="bigint" not-null="true"/>
</property>
<property name="Other" type="String">
<column name="other" length="50" sql-type="varchar" not-null="true"/>
</property>
这样改过来就可以了。如果Id为Int64的那列在数据库更新异常的时候要改成
<property name="Id" type="Int64" update="false" insert="false">
<column name="id" length="8" sql-type="bigint" not-null="true"/>
</property>
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就不会有异常出现了。