NHibernate 命名查询和二级缓存

Question

我在 hibernate.cfg.xml 中有以下映射

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
               assembly="Domain.Core"
               namespace="Domain.Core">
<class name="Industry" table="INDUSTRY">
<cache usage="read-write" region="IndustryCache" include="all"/>
<id name="Id" type="Int64" column="IID">
  <generator class="sequence">
    <param name="sequence">INDUSTRY_SEQ</param>
  </generator> 
</id>
<version name="Version" column="VERSION" access="property" unsaved-value="null" generated="never"/>
<property name="CreationTime" column="CREATE_DATE" type="DateTime" not-null="true" />
<property name="CreatedBy" column="CREATE_USER" type="String" not-null="true" />
<property name="LastUpdateTime" column="MODIFY_DATE"  type="DateTime" not-null="false" />
<property name="LastUpdateBy" column="MODIFY_USER" type="String" not-null="false" />
<property name="Code" column="INDUSTRY" type="String" not-null="false" />
<map name="Resources" table="INDUSTRY_TL"  fetch="subselect">
  <cache region="IndustryCache" usage="read-write" include="all"/>
  <key column="INDUSTRY_ID"/>
  <composite-index class="Framework.Globalization.UILanguage, Framework">
    <key-property name="Code" column="LANG" access="property" />
  </composite-index>
  <composite-element class="Industry+Translation">
    <property name="Name" column="Industry_TL" />
  </composite-element>
</map>
</class>
<query name="GetIndustyOrderByName">
<![CDATA[
from Industry as i left join fetch i.Resources as res where INDEX(res) = :lang order  
by res.Name
]]>
</query>    
</hibernate-mapping>

和以下配置

<property name="show_sql">true</property>
<property name='proxyfactory.factory_class'>NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
<property name='prepare_sql'>true</property>
<property name='query.substitutions'>Y=true,N=false,0=false,1=true</property>
<property name="generate_statistics">true</property>
<property name="cache.use_second_level_cache">true</property>
<property name="cache.provider_class">Framework.Cache.SossCacheProvider, Framework.Cache.SossNHibernateCache</property>
<property name="cache.use_query_cache">true</property>

现在，当我使用调用映射集合的 SetCacheable(true) 运行命名查询时，它不会到达二级缓存。有什么理由吗？

更一般地说，有没有办法将命名查询的结果集放入二级缓存？

谢谢！

Answer 1

为了让查询使用二级缓存，必须完成两件事：
1. 在 NHibernate 配置中启用查询缓存：

    <property name="cache.use_query_cache">true</property>

2. 在获取 IQuery 实例时启用查询缓存：

    IQuery = session.GetNamedQuery("from Industry as i left join fetch i.Resources as res where INDEX(res) = :lang order by res.Name")
      .SetCacheable(true)
      .Setxxx();

这些设置会导致查询结果放入二级缓存中。但二级查询缓存仅存储实体的标识符，而不存储实体本身。为了使查询的执行完全避开数据库，实体也必须被缓存。有关交互的更多说明，请参阅 NH 文档二级缓存。