NHibernate的：映射一个连接在连接表NHibernate
我有一个观点连接3个表在一起的链条，我需要用NHibernate的映射，以取代不作任何修改到数据库中。这可能吗？ 这是我认为一个简单的例子：
SELECT tblTable1 *，tblTable2 *，tblTable3.MyProperty从tblTable1
OUTER JOIN
tblTable2 ON tblTable1.Table1Key = tblTable2.Table1Key
OUTER JOIN
tblTable3 ON tblTable2.Table2Key = tblTable3.Table2Key
所以basicaly我们选择tblTable1并加入tblTable2这对我的作品在NHibernate的。我的问题是tblTable3。如何加入它从连接表tblTable2的属性？
当我做这样的映射，我收到了查询，试图加入tblTable3上Table1Key出于某种原因。
＆LT;类名=MyClass的表=tblTable1＆GT;
＆LT; ID名称=Table1Key＆GT;
＆LT;生成器类=身份/＆GT;
＆LT; / ID＆GT;
＆LT;属性名=.../＆GT;
＆LT;连接表=tblTable2＆GT;
＆LT;键列=Table1Key/＆GT;
＆LT;属性名=.../＆GT;
＆LT; /加入＆GT;
＆LT;连接表=tblTable3＆GT;
＆LT;键列=Table2Key ??? /＆GT;
＆LT;属性名=.../＆GT;
＆LT; /加入＆GT;
＆LT; /类＆GT;
解决方案
在新罕布什尔州，你不能参加联接。唯一的办法是让一个参考，它不basicly同样的事情
＆LT;类名=MyClass的表=tblTable1＆GT;
＆LT; ID名称=Table1Key＆GT;
＆LT;生成器类=身份/＆GT;
＆LT; / ID＆GT;
＆LT;属性名=.../＆GT;
＆LT;多到一个表=tblTable2懒惰=假＆GT;
＆LT;键列=Table1Key/＆GT;
＆LT;属性名=.../＆GT;
＆LT; /多到一＆GT;
＆LT; /类＆GT;
＆LT;类名=MyClass2的表=tblTable2＆GT;
＆LT;连接表=tblTable3＆GT;
＆LT;键列=Table2Key/＆GT;
＆LT;属性名=.../＆GT;
＆LT; /加入＆GT;
＆LT; /类＆GT;
MyClass类
{
公共虚拟MyClass2的MyClass2的{获得;组; }
公共虚拟INT MyClass2_MyProperty
{
{返回MyClass2.MyProperty; }
集合{MyClass2.MyProperty =价值; }
}
}
类MyClass2的
{
公共虚拟myProperty的INT {获得;组; }
}
编辑选项2：如果您不希望 MyClass2的也许你可以调整这一点：
＆LT;类名=MyClass的表=tblTable2＆GT; ＆LT; - 以表2为主要表
＆LT; ID名称=Table1Key＆GT;
＆LT;生成器类=序列＆GT; ＆LT; - 可问题就在这里，使用序列（直接）呢？
＆LT; PARAM NAME =sequencename＆GT; table1_id_squence＆LT; /参数＆GT; //不知道sequencename
＆LT; /发电机＆GT;
＆LT; / ID＆GT;
＆LT;属性名=.../＆GT;
＆LT;连接表=tblTable1＆GT;
＆LT;键列=Table1Key/＆GT;
＆LT;属性名=.../＆GT;
＆LT; /加入＆GT;
＆LT;连接表=tblTable3＆GT;
＆LT;键列=Table2Key/＆GT;
＆LT;属性名=.../＆GT;
＆LT; /加入＆GT;
＆LT; /类＆GT;
I have a view joining 3 tables together in a chain that i need to replace with a NHibernate mapping without any changes to the database. Is this possible? This is a simplified example of my view:
SELECT tblTable1.*,tblTable2.*,tblTable3.MyProperty FROM tblTable1
OUTER JOIN
tblTable2 ON tblTable1.Table1Key = tblTable2.Table1Key
OUTER JOIN
tblTable3 ON tblTable2.Table2Key = tblTable3.Table2Key
so basicaly we select tblTable1 and join tblTable2 this works for me in NHibernate. My problem is tblTable3. How do i join it on a property from the joined table tblTable2?
When i do the mapping like this i get a query trying to join tblTable3 on Table1Key for some reason.
<class name="MyClass" table="tblTable1">
<id name="Table1Key">
<generator class="identity"/>
</id>
<property name="..." />
<join table="tblTable2">
<key column="Table1Key" />
<property name="..." />
</join>
<join table="tblTable3">
<key column="Table2Key???" />
<property name="..." />
</join>
</class>
解决方案
in NH you can't join in a join. the only way is to make it a reference, which does basicly the same thing
<class name="MyClass" table="tblTable1">
<id name="Table1Key">
<generator class="identity"/>
</id>
<property name="..." />
<many-to-one table="tblTable2" lazy="false">
<key column="Table1Key" />
<property name="..." />
</many-to-one>
</class>
<class name="MyClass2" table="tblTable2">
<join table="tblTable3">
<key column="Table2Key" />
<property name="..." />
</join>
</class>
class MyClass
{
public virtual MyClass2 MyClass2 { get; set; }
public virtual int MyClass2_MyProperty
{
get { return MyClass2.MyProperty; }
set { MyClass2.MyProperty = value; }
}
}
class MyClass2
{
public virtual int MyProperty { get; set; }
}
Edit Option 2: if you dont want MyClass2 Maybe you can tweak this:
<class name="MyClass" table="tblTable2"> <-- take table2 as the main table
<id name="Table1Key">
<generator class="sequence"> <-- can be problem here, use sequence (directly) instead?
<param name="sequencename">table1_id_squence</param> // not sure about "sequencename"
</generator>
</id>
<property name="..." />
<join table="tblTable1">
<key column="Table1Key" />
<property name="..." />
</join>
<join table="tblTable3">
<key column="Table2Key" />
<property name="..." />
</join>
</class>
