[NHibernate]視圖處理

 1 namespace Wolfy.Shop.Domain.Entities
 2 {
 3     /// <summary>
 4     /// 描述：客戶訂單視圖持久化類
 5     /// 創建人：wolfy
 6     /// 創建時間：2014-11-08
 7     /// </summary>
 8     public class CustomerOrderView
 9     {
10         /// <summary>
11         /// 客戶id
12         /// </summary>
13         public virtual Guid CustomerID { get;private set; }
14         /// <summary>
15         /// 客戶姓名
16         /// </summary>
17         public virtual string CustomerName { get; private set; }
18         /// <summary>
19         /// 客戶住址
20         /// </summary>
21         public virtual string CustomerAddress { get; private set; }
22         /// <summary>
23         /// 訂單id
24         /// </summary>
25         public virtual Guid OrderID { private set; get; }
26         /// <summary>
27         /// 下單時間
28         /// </summary>
29         public virtual DateTime OrderDate {private set; get; }
30     }
31 }

注意：對視圖最常用的是查詢操作，視圖是一張虛表，也就是只讀的（數據的來源是來自物理表的）。所以這里將持久化類的屬性設置為只讀的（private set）就可以了，如果真想修改數據了，就通過修改物理表的數據。
編寫映射文件CustomerOrderView.hbm.xml

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <!--assembly:程序集，namespace:命名空間-->
 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     <!--主鍵-->
 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中使用視圖的時候，最容易忽略的就是沒有給視圖指定主鍵，這種情況下很容易出錯。

2，注意映射文件中class節點指定mutable="false"屬性（對對象的修改不能持久化到數據庫中）。

3，記得添加過映射文件，修改hbm.xml屬性為嵌入資源

測試

獲取某客戶下面所有的訂單信息。

 1         /// <summary>
 2         /// 根據客戶id查詢視圖，獲得客戶信息，及下單信息。
 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         }

此時會有一個異常

 1 “NHibernate.InvalidProxyTypeException”類型的異常在 NHibernate.dll 中發生，但未在用戶代碼中進行處理
 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'

意思已經很明白了，說屬性的set方法，應該是Public或者Protect virtual的。解決辦法，要么修改回默認的public，要么修改映射文件的默認加載方式將hibernate-mapping的default-lazy屬性設置為false。讓他立即加載。

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <!--assembly:程序集，namespace:命名空間-->
 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     <!--主鍵-->
 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>