没有键的NHibernate映射

Question

I have these two classes

[DataServiceKey("Id")]
public class EmailMessage
{
    [DataMember]
    public virtual long Id { get; set; }

    [DataMember]
    public virtual string Scope { get; set; }

    [DataMember]
    public virtual long ScopeId { get; set; }

    ...

    [DataMember]
    public virtual IList<BinaryDataView> Attachments { get; set; }
}

and

public class BinaryDataView
{
    [DataMember]
    public virtual long BinaryId { get; set; }

    [DataMember]
    public virtual string ExternalLink { get; set; }
}

I am trying to create a propher nhibernate mapping for them but, data base are old enough and I can't use forenkeys. Both data bases (tEmail and tBinaryData) contains fields Scope and ScopeId and I need to use them to get BinaryData.

So this is how my classes in hbm.xml looks like:

 <class name="EmailMessage" table="tEmail">
    <id name="Id">
      <column name="EmailId" sql-type="bigint"/>
      <generator class="native" />
    </id>
    <property name="DataOwnerId" />
    <property name="Scope"/>
    <property name="ScopeId"/>
    <property name="From" column="[From]"/>
    <property name="To" column="[To]"/>
    <property name="Subject"/>
    <property name="Body"/>
    <bag name="Attachments" lazy="false" fetch="join" generic="true">
      <key>
        <column name="Scope" />
        <column name="ScopeId" />
      </key>
      <one-to-many class="Entities.BinaryDataView,Entities" not-found="ignore"/>
    </bag>
  </class>

and

  <class name="BinaryDataView" table="tBinaryData" >
    <id name="BinaryId">
      <column name="BinaryId" sql-type="bigint"/>
      <generator class="native" />
    </id>
    <property name="ExternalLink"/>
  </class>

Right now I'm getting the: Foreign key (FK66731BD76FED2100:tBinaryData [Scope, ScopeId])) must have same number of columns as the referenced primary key (tEmail [EmailId]) error. So, there is my question: Where am I wrong and what I'm doing wrong? How can I create this mapping without using forenkeys for Scope and ScopeId?

And sorry for my bad English.

---

Update: Managed to create mapping. At least right now its working:

  <class name="EmailMessage" table="tEmail">
    <id name="Id">
      <column name="EmailId" sql-type="bigint"/>
      <generator class="native" />
    </id>
    <property name="DataOwnerId" />
    <property name="Scope" />
    <property name="ScopeId" />
    <properties name="ScopeInfo">
      <property name="Scope" column="Scope"/>
      <property name="ScopeId" column="ScopeId"/>
    </properties>
    <property name="From" column="[From]"/>
    <property name="To" column="[To]"/>
    <property name="Subject"/>
    <property name="Body"/>
    <bag name="Attachments" lazy="false" fetch="join" generic="true">
      <key property-ref="ScopeInfo" foreign-key="none">
        <column name="Scope" />
        <column name="ScopeId" />
      </key>
      <one-to-many class="Entities.BinaryDataView,Entities" not-found="ignore"/>
    </bag>
  </class>

Answer 1

The problem is EmailMessage exports two keys, scope and scopeId as attachments, but your BinaryDataView has only one ID BinaryID. The exported keys must match to ID of the otherside. The error message actually has nothing to do with ForeignKeys in the DB. Your mapping is wrong. Consider adding a composite id to BinaryDataView , with scope and scopeid