如何为多映射配置nHibernate

使用nHibernate 3.2、C#4.0、SQL Server 2008 R2 Express

我有两个业务实体——Broker和Market。它们分别存储在brokers和markets表中。我还有一个brokerMarkets表，它有一个额外的列，叫做MinIncrement。Broker和Market之间有很多关系，但只有当我想存储MinIncrement值时（即它是可选的）。我的课程是这样的：

public class Market : BusinessBase
{
    public Market() {}
    public virtual int Id { get; set; }
    public virtual string Symbol { get; set; }
    public virtual string Description { get; set; }
}
public class Broker : BusinessBase
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
    public virtual bool IsDefault { get; set; }
    public virtual bool IsActive { get; set; }
    public virtual ISet<Account> Accounts { get; set; }
}
public class BrokerMarket : Market
{
    public BrokerMarket() { }
    public virtual Broker Broker {get; set;}
    public virtual decimal MinIncrement { get; set; }
}

我的映射文件如下所示：Market.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="MooDB"
                   namespace="MooDB.BusinessLayer">
    <class name="MooDB.BusinessLayer.Market,MooDB" table="markets">
        <id name="Id" column="marketId" type="Int32" unsaved-value="0">
            <generator class="native" />
        </id>           
        <version name="Version" column="version" type="integer" unsaved-value="0" />
        <property name="Symbol" column="symbol" type="String" length="10" not-null="true" />
        <property name="Description" column="description" type="String" length="30" not-null="true" />
        <set name="Brokers" generic="true" table="brokerMarkets">
            <key column="marketId" />
            <many-to-many column="brokerId" class="MooDB.BusinessLayer.Broker,MooDB" />            
        </set>
    </class>
</hibernate-mapping>

经纪人.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="MooDB"
                   namespace="MooDB.BusinessLayer">
    <class name="MooDB.BusinessLayer.Broker,MooDB" table="brokers">
        <id name="Id" column="brokerId" type="Int32" unsaved-value="0">
            <generator class="native" />
        </id>
        <version name="Version" column="version" type="integer" unsaved-value="0" />
        <property name="Name" column="broker" type="String" length="50" not-null="true" />
        <property name="IsActive" column="isActive" type="bool" not-null="true" />
        <property name="IsDefault" column="isDefault" type="bool" not-null="true" />
        <set name="Markets" generic="true" table="brokerMarkets">
            <key column="brokerId" />
            <many-to-many column="marketId" class="MooDB.BusinessLayer.Market,MooDB" />
        </set>
        <set name="Accounts" table="accounts" generic="true" inverse="true">
            <key column="brokerId" />
            <one-to-many class="MooDB.BusinessLayer.Account,MooDB" />
        </set>
    </class>    
</hibernate-mapping>

在我的数据访问层中，我有一种添加BrokerMarket:的方法

public void AddBrokerMarket(BrokerMarket bm)
{
    using (ITransaction tx = _session.BeginTransaction())
    {
        try
        {
            _session.Save(bm);
            _session.Flush();
            tx.Commit();
        }
        catch (HibernateException)
        {
            tx.Rollback();
            throw;
        }
    }
}

在我的单元测试中，我尝试添加一个BrokerMarket，如下所示：

[Test]
public void CanAddBrokerMarket()
{
    Broker broker = _provider.GetBrokerById(1);
    Market market = _provider.GetMarketById(2);
    var brokerMarket = new BrokerMarket { Broker = broker, Description = market.Description, Symbol = market.Symbol, MinIncrement = 0.01M };
    _provider.AddBrokerMarket(brokerMarket);
}

当我运行测试时，我得到了这个错误：

正在运行测试。测验"MooDBTests/MooDB/Tests/DataLayerTests/CanAddBrokerMarket"失败：消息NHibernate.MappingException：没有持续时间：MooDB.BusinessLayer.BrokerMarket堆栈跟踪NHibernate.Impl.SessionFactoryImpl.GetEntityPersister（字符串entityName）在NHibernate.Impl.SessionImpl.GetEntityPersister（字符串entityName，Object obj）NHibernate.Event.Default.AbstractSaveEventListener.SaveWithGeneratedId（对象entity，String entityName，Object anything，IEventSource source，在处需要布尔值ImmediateIdAccess）NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.SaveWithGeneratedOrRequestedId（SaveOrUpdateEvent事件）NHibernate.Event.Default.DefaultSaveEventListener.SaveWithGeneratedOrRequestedId（SaveOrUpdateEvent事件）NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.EntityIsTransient（SaveOrUpdateEvent事件）NHibernate.Event.Default.DefaultSaveEventListener.PerformSaveOrUpdate（SaveOrUpdateEvent事件）NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate（SaveOrUpdateEvent事件）在NHibernate.Impl.SessionImpl.FireSave（SaveOrUpdateEvent事件）在NHibernate.Impl.SessionImpl.Save（对象对象）NHibernateDataProvider.cs（91,0）：位于MooDB.DataLayer.NHibernateDataProvider.AddBrokerMarket（经纪市场bm）DataLayerTests.cs（81,0）：位于MooDB.Tests.DataLayerTests.CanAddBrokerMarket（）

我不确定我做错了什么。我需要在Market类中添加一个Broker集合，在Broker类中添加Market集合吗？我确实试过了，但我也犯了同样的错误，我想我在概念上遗漏了一些东西。

更新

我已经实施了以下更改：Market.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="MooDB"
                   namespace="MooDB.BusinessLayer">
    <class name="MooDB.BusinessLayer.Market,MooDB" table="markets">
        <id name="Id" column="marketId" type="Int32" unsaved-value="0">
            <generator class="native" />
        </id>           
        <version name="Version" column="version" type="integer" unsaved-value="0" />
        <property name="Symbol" column="symbol" type="String" length="10" not-null="true" />
        <property name="Description" column="description" type="String" length="30" not-null="true" />
      <map name="BrokerMarkets" table="brokerMarkets" lazy="true" cascade="none">
        <cache usage="read-write"/>
        <key column="marketId" />
        <index column="brokerId" type="Int32" />
        <composite-element class="MooDB.BusinessLayer.BrokerMarket,MooDB">
          <parent name="Market"/>
          <property name="MinIncrement" column="minIncrement" type="decimal" />
          <many-to-one name="Broker" class="MooDB.BusinessLayer.Broker,MooDB" column="brokerId" />
        </composite-element>        
      </map>
    </class>
</hibernate-mapping>

经纪人.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="MooDB"
                   namespace="MooDB.BusinessLayer">
    <class name="MooDB.BusinessLayer.Broker,MooDB" table="brokers">
        <id name="Id" column="brokerId" type="Int32" unsaved-value="0">
            <generator class="native" />
        </id>
        <version name="Version" column="version" type="integer" unsaved-value="0" />
        <property name="Name" column="broker" type="String" length="50" not-null="true" />
        <property name="IsActive" column="isActive" type="bool" not-null="true" />
        <property name="IsDefault" column="isDefault" type="bool" not-null="true" />
        <set name="Accounts" table="accounts" generic="true" inverse="true">
            <key column="brokerId" />
            <one-to-many class="MooDB.BusinessLayer.Account,MooDB" />
        </set>
    </class>    
</hibernate-mapping>

Market类：

public class Market : BusinessBase
{
    public Market() {}
    public virtual int Id { get; set; }
    public virtual string Symbol { get; set; }
    public virtual string Description { get; set; }
    public virtual ISet<BrokerMarket> BrokerMarkets { get; set; } //added this line
}

BrokerMarket类

public class BrokerMarket : Market
{
    public BrokerMarket() { }
    public virtual Broker Broker {get; set;}
    public virtual Market Market { get; set; } // added this line
    public virtual decimal MinIncrement { get; set; }
}

其他一切都没有改变。我再次运行单元测试，得到：

正在运行测试。测验"MooDBTests/MooDB/Tests/DataLayerTests/CanAddBrokerMarket"失败：DataLayerTests 中的Message TestFixtureSetUp失败

测试"MooDBTests/MooDB/Tests/DataLayerTests"失败：消息设置：NHibernate.MappingException：的映射中重复列收藏：MooDB.BusinessLayer.Market.BrokerMarkets专栏：brokerId

更新2

如果我删除

<index column="brokerId" type="Int32" />

在Market.hbm.xml中，我在运行单元测试时收到了以下错误：

正在运行测试。测验"MooDBTests/MooDB/Tests/DataLayerTests/CanAddBrokerMarket"失败：DataLayerTests 中的Message TestFixtureSetUp失败

测试"MooDBTests/MooDB/Tests/DataLayerTests"失败：消息设置：NHibernate.MappingException：MooDB.Mappings.Market.hbm.xml（17,10）：XML验证错误：命名空间中的元素"map"urn:nhibernate-mapping-2.2"具有无效的子元素命名空间"urn:nhibernate-mapping-2.2"中的"composite element"。的列表需要可能的元素：'map key，composite map key，映射键多对多，索引，复合索引，索引多对多，将many索引到命名空间'urn:nhibernate-mapping-2.2'中的任意'---->System.Xml.Schema.XmlSchemaValidationException：中的元素"map"命名空间"urn:nhibernate-mapping-2.2"具有无效的子元素命名空间"urn:nhibernate-mapping-2.2"中的"composite element"。的列表需要可能的元素：'map key，composite map key，映射键多对多，索引，复合索引，索引多对多，将多个索引到命名空间"urn:nhibernate-mapping-2.2"中的任意"。