[NHibernate]视图处理

 1 namespace Wolfy.Shop.Domain.Entities
 2 {
 3     /// <summary>
 4     /// 描述：客户订单视图持久化类
 5     /// 创建人：wolfy
 6     /// 创建时间：2014-11-08
 7     /// </summary>
 8     public class CustomerOrderView
 9     {
10         /// <summary>
11         /// 客户id
12         /// </summary>
13         public virtual Guid CustomerID { get;private set; }
14         /// <summary>
15         /// 客户姓名
16         /// </summary>
17         public virtual string CustomerName { get; private set; }
18         /// <summary>
19         /// 客户住址
20         /// </summary>
21         public virtual string CustomerAddress { get; private set; }
22         /// <summary>
23         /// 订单id
24         /// </summary>
25         public virtual Guid OrderID { private set; get; }
26         /// <summary>
27         /// 下单时间
28         /// </summary>
29         public virtual DateTime OrderDate {private set; get; }
30     }
31 }

注意：对视图最常用的是查询操作，视图是一张虚表，也就是只读的（数据的来源是来自物理表的）。所以这里将持久化类的属性设置为只读的（private set）就可以了，如果真想修改数据了，就通过修改物理表的数据。
编写映射文件CustomerOrderView.hbm.xml

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <!--assembly:程序集，namespace:命名空间-->
 3 <hibernate-mapping  xmlns="urn:nhibernate-mapping-2.2" assembly="Wolfy.Shop.Domain"  namespace="Wolfy.Shop.Domain.Entities">
 4   <class name="Wolfy.Shop.Domain.Entities.CustomerOrderView,Wolfy.Shop.Domain" table="VW_CusomterOrder" mutable="false">
 5     <!--主键-->
 6     <id name="CustomerID" type="Guid" unsaved-value="null">
 7       <column name="CustomerID" sql-type="uniqueidentifier" not-null="true" unique="true"/>
 8       <generator class="assigned"></generator>
 9     </id>
10     <property name="CustomerName" column ="CustomerName" type="string"
11                          length="16" not-null="false" />
12     <property name ="CustomerAddress" column="CustomerAddress" type="string"
13                          length="128" not-null="false" />
14     <property name="OrderID" column="OrderID" type="Guid" not-null="true"/>
15     <property name="OrderDate" column="OrderDate" type="DateTime" />
16   </class>
17 </hibernate-mapping>

注意：1，在nhibernate中使用视图的时候，最容易忽略的就是没有给视图指定主键，这种情况下很容易出错。

2，注意映射文件中class节点指定mutable="false"属性（对对象的修改不能持久化到数据库中）。

3，记得添加过映射文件，修改hbm.xml属性为嵌入资源

测试

获取某客户下面所有的订单信息。

 1         /// <summary>
 2         /// 根据客户id查询视图，获得客户信息，及下单信息。
 3         /// </summary>
 4         /// <param name="guid"></param>
 5         /// <returns></returns>
 6         public IList<CustomerOrderView> GetCustomerOrderViewByCustomerId(Guid customerID)
 7         {
 8             ISession session = NHibernateHelper.GetSession();
 9             return session.CreateCriteria(typeof(CustomerOrderView))
10                 .Add(Restrictions.Eq("CustomerID", customerID))
11                 .List<CustomerOrderView>();
12         }

此时会有一个异常

 1 “NHibernate.InvalidProxyTypeException”类型的异常在 NHibernate.dll 中发生，但未在用户代码中进行处理
 2 
 3 其他信息: The following types may not be used as proxies:
 4 
 5 Wolfy.Shop.Domain.Entities.CustomerOrderView: method set_CustomerID should be 'public/protected virtual' or 'protected internal virtual'
 6 
 7 Wolfy.Shop.Domain.Entities.CustomerOrderView: method set_CustomerName should be 'public/protected virtual' or 'protected internal virtual'
 8 
 9 Wolfy.Shop.Domain.Entities.CustomerOrderView: method set_CustomerAddress should be 'public/protected virtual' or 'protected internal virtual'
10 
11 Wolfy.Shop.Domain.Entities.CustomerOrderView: method set_OrderID should be 'public/protected virtual' or 'protected internal virtual'
12 
13 Wolfy.Shop.Domain.Entities.CustomerOrderView: method set_OrderDate should be 'public/protected virtual' or 'protected internal virtual'

意思已经很明白了，说属性的set方法，应该是Public或者Protect virtual的。解决办法，要么修改回默认的public，要么修改映射文件的默认加载方式将hibernate-mapping的default-lazy属性设置为false。让他立即加载。

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <!--assembly:程序集，namespace:命名空间-->
 3 <hibernate-mapping  xmlns="urn:nhibernate-mapping-2.2" assembly="Wolfy.Shop.Domain"  namespace="Wolfy.Shop.Domain.Entities" default-lazy="false">
 4   <class name="Wolfy.Shop.Domain.Entities.CustomerOrderView,Wolfy.Shop.Domain" table="VW_CusomterOrder" mutable="false">
 5     <!--主键-->
 6     <id name="CustomerID" type="Guid" unsaved-value="null">
 7       <column name="CustomerID" sql-type="uniqueidentifier" not-null="true" unique="true"/>
 8       <generator class="assigned"></generator>
 9     </id>
10     <property name="CustomerName" column ="CustomerName" type="string"
11                          length="16" not-null="false" />
12     <property name ="CustomerAddress" column="CustomerAddress" type="string"
13                          length="128" not-null="false" />
14     <property name="OrderID" column="OrderID" type="Guid" not-null="true"/>
15     <property name="OrderDate" column="OrderDate" type="DateTime" />
16   </class>
17 </hibernate-mapping>