Fluent nhibernate 每个子类的表映射在获取时失败

代码编译良好，但NUnit测试失败，出现以下错误：
09:59:00789错误[TestRunnerThread]AbstractBatcher[（null）]-无法执行查询：选择workflow0.Id作为Id13\u 0，workflow0.Name作为Name13\u 0，workflow0.ModifiedById作为Modified3\u 13\u 0，workflow0.ModifiedDate作为Modified4\u 13\u 0，workflow0\u0.CreatedById作为CreatedB5\u 13\u 0，workflow0.CreatedDate作为CreatedD6\u 13\u 0，workflow0.Version作为Version13\u 0\u，workflow0\u.WorkflowTemplateID作为Workflow8\u 13\u 0\u，workflow0\u 1\u.PBMId作为PBMId14\u 0\u，当workflow0_1_.Workflow_id不为null时的情况，然后当workflow0_.id不为null时的情况，然后从workflow0_结束为clazz_0_工作流0左外部联接WorkflowRDSCostReport workflow0_1_在workflow0上。id=workflow0_1_.Workflow_id，其中workflow0_.id=@p0 System.Data.SqlClient.SqlException（0x80131904）：列名“Workflow_id”无效

如果我删除包含子类映射的文件，测试将正常运行。父工作流以“Id”作为主键列。子项是WorkflowRDSCstreport，其中“WorkflowId”作为主键和FK关系。WorkflowTemplate是一个单独的表，可以正常工作。代码：

Workflow.cs：

public class Workflow: EditableEntityBase<int>
{
    #region properties

    public virtual WorkflowTemplate WorkflowTemplate { get; set; }
    public virtual string Name { get; set; }

    #endregion properties
}

WorkflowMap.cs：

public class WorkflowMap: ClassMap<Workflow>
{
    public WorkflowMap()
    {
        Table("Workflow");

        Id(x => x.Id, "Id")
            .GeneratedBy.Identity();

        References(x => x.WorkflowTemplate, "WorkflowTemplateID")
           .Not.Nullable()
           .Not.LazyLoad()
           .Cascade.None();

        //Name
        Map(x => x.Name, "Name")
            .Nullable();

        //ModifiedById
        Map(x => x.ModifiedById, "ModifiedById")
            .Not.Nullable();
        //ModifiedDate
        Map(x => x.ModifiedDate, "ModifiedDate")
            .CustomType(typeof(DateTime))
            .Not.Nullable();
        //CreatedById
        Map(x => x.CreatedById, "CreatedById")
            .Not.Nullable();
        //CreatedDate
        Map(x => x.CreatedDate, "CreatedDate")
            .CustomType(typeof(DateTime))
            .Not.Nullable();
        //Version
        Map(x => x.Version, "Version")
            .Not.Nullable();
    }
}

public class WorkflowMap: ClassMap<Workflow>
{
    public WorkflowMap()
    {
        Table("Workflow");

        Id(x => x.Id, "Id")
            .GeneratedBy.Identity();

        References(x => x.WorkflowTemplate, "WorkflowTemplateID")
           .Not.Nullable()
           .Not.LazyLoad()
           .Cascade.None();

        //Name
        Map(x => x.Name, "Name")
            .Nullable();

        //ModifiedById
        Map(x => x.ModifiedById, "ModifiedById")
            .Not.Nullable();
        //ModifiedDate
        Map(x => x.ModifiedDate, "ModifiedDate")
            .CustomType(typeof(DateTime))
            .Not.Nullable();
        //CreatedById
        Map(x => x.CreatedById, "CreatedById")
            .Not.Nullable();
        //CreatedDate
        Map(x => x.CreatedDate, "CreatedDate")
            .CustomType(typeof(DateTime))
            .Not.Nullable();
        //Version
        Map(x => x.Version, "Version")
            .Not.Nullable();
    }
}

public class WorkflowRDSCostReportMap : SubclassMap<WorkflowRDSCostReport>
{
    public WorkflowRDSCostReportMap()
    {
        Table("WorkflowRDSCostReport");

        Map(x => x.PBMId, "PBMId")
            .Not.Nullable();
    }
}

public class WorkflowRepository : RepositoryBase<Workflow, int>
{
    public WorkflowRepository() : base() { }
}

namespace Test
{
[TestFixture]
public class WorkflowRepositoryTest
{
    #region Class Members

    private Workflow _workflow;
    private WorkflowRepository _workflowRepository;
    private WorkflowTemplate _workflowTemplate;
    private WorkflowTemplateRepository _workflowTemplateRepository;

    private WorkflowRDSCostReport _workflowRDSCostReport;

    #endregion Class Members


    #region Setup

    [TestFixtureSetUp]
    public void TestFixtureSetup()
    {
        RepositoryBase.UseDevDatabase = true;

        _workflowTemplate = TestHelper.CreateWorkflowTemplate();
        _workflowTemplateRepository = new WorkflowTemplateRepository();
        _workflowTemplateRepository.Save(_workflowTemplate);
    }

    [SetUp]
    public void SetUp()
    {
        _workflow = TestHelper.CreateWorkflow(_workflowTemplate);
        _workflowRepository = new WorkflowRepository();

        _workflowRDSCostReport = TestHelper.CreateWorkflowRDSCostReport();
    }

    #endregion Setup
    [Test]
    public void DeleteTest()
    {
        _workflowRepository.Save(_workflow);
        Workflow readEntity = _workflowRepository.Fetch(_workflow.Id);
        Assert.NotNull(readEntity);

        _workflowRepository.Delete(_workflow);

        readEntity = _workflowRepository.Fetch(_workflow.Id);
        Assert.IsNull(readEntity);
        _workflow = null;
    }

 #region TearDown

    [TearDown]
    public void TearDown()
    {
        if (_workflow != null)
        {
            _workflowRepository.Delete(_workflow);
        }

        if (_workflowRDSCostReport != null)
        {
            _workflowRepository.Delete(_workflowRDSCostReport);
        }
    }

    [TestFixtureTearDown]
    public void TestFixtureTearDown()
    {
        _workflowTemplateRepository.Delete(_workflowTemplate);
    }

    #endregion // TearDown
}
}