如何使用Fluent NHibernate自动映射在TPH中的一对多中使用我的抽象基类

我正在尝试使用Giveaway.Giveable来接受Giveable的任何子类，但由于Giveable是一个抽象基类，因此它实际上没有映射。我使用的是"按层次表"，而不是TPT。

我加入的课程是为了帮助其他用户，并提供更多关于NHibernate的真实世界示例，请原谅所有的代码。

异常：Giveaway表中的关联引用了未映射的类：Giveable

AutoMap.AssemblyOf<Giveaway>(cfg).UseOverridesFromAssemblyOf<UserMappingOverride>()
                                    .Conventions.Add(
                                        PrimaryKey.Name.Is(x => "ID"),
                                        DefaultLazy.Always(),
                                        DefaultCascade.Delete(),
                                        DynamicInsert.AlwaysTrue(),
                                        DynamicUpdate.AlwaysTrue(),
                                        OptimisticLock.Is(x => x.Dirty()),
                                        ForeignKey.EndsWith("ID")))).ExposeConfiguration(BuildSchema)
public abstract class Giveable
{
    ISet<Giveaway> giveaways;
    public Giveable() : base()
    {
        giveaways = new HashedSet<Giveaway>();
    }
    public virtual ISet<Giveaway> Giveaways
    {
        get { return giveaways; }
        set { giveaways = value; }
    }
    public virtual int ID { get; set; }
    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        var toCompareWith = obj as Giveable;
        return toCompareWith != null && ((ID == toCompareWith.ID));
    }
    public override int GetHashCode()
    {
        int toReturn = base.GetHashCode();
        toReturn ^= ID.GetHashCode();
        return toReturn;
    }
}
public class Giveaway
{
    ISet<Entry> entries;
    public Giveaway() : base()
    {
        entries = new HashedSet<Entry>();
        CreatedDate = DateTime.UtcNow;
    }
    public virtual DateTime CreatedDate { get; private set; }
    public virtual DateTime? EndDate { get; set; }
    public virtual ISet<Entry> Entries
    {
        get { return entries; }
        set { entries = value; }
    }
    public virtual Giveable Giveable { get; set; }
    public virtual int ID {get;set;}
    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        var toCompareWith = obj as Giveaway;
        return toCompareWith != null && ((ID == toCompareWith.ID));
    }
    public override int GetHashCode()
    {
        int toReturn = base.GetHashCode();
        toReturn ^= ID.GetHashCode();
        return toReturn;
    }
}
public class GiveableMappingOverride : IAutoMappingOverride<Giveable>
    {
        public void Override(AutoMapping<Giveable> mapping)
        {
            mapping.DiscriminateSubClassesOnColumn("GiveableType");
            mapping.Map(x => x.Name).Length(200).Not.Nullable();
            mapping.Map(x => x.ImageName).Length(200).Nullable();
            mapping.Map(x => x.ReleaseDate).Not.Nullable();
            mapping.HasMany(x => x.Giveaways)
                .Fetch.Select()
                .AsSet()
                .Inverse()
                .LazyLoad();
        }
    }
public class GiveawayMappingOverride : IAutoMappingOverride<Giveaway>
    {
        public void Override(AutoMapping<Giveaway> mapping)
        {
            mapping.Map(x => x.ThingID).Length(20).Nullable();
            mapping.Map(x => x.Text).Length(2000).Not.Nullable();
            mapping.Map(x => x.CreatedDate).Not.Nullable();
            mapping.Map(x => x.Platform).Not.Nullable();
            mapping.Map(x => x.Type).Not.Nullable();
            mapping.HasMany(x => x.Entries);
            mapping.References(x => x.Giveable).Not.Nullable();
            mapping.References(x => x.User).Not.Nullable();
            mapping.References(x => x.Winner);
        }
    }

        public class AppMappingOverride : IAutoMappingOverride<App>
        {
            public void Override(AutoMapping<App> mapping)
            {
                mapping.DynamicUpdate();
                mapping.DynamicInsert();
                mapping.HasManyToMany(x => x.Subscriptions).Inverse();
                mapping.HasManyToMany(x => x.Users).Inverse();
            }
        }
        public class SubscriptionMappingOverride : IAutoMappingOverride<Subscription>
        {
            public void Override(AutoMapping<Subscription> mapping)
            {
                mapping.DynamicInsert();
                mapping.DynamicUpdate();
                mapping.HasManyToMany(x => x.Apps);
            }
        }