I have this very simple class

public class ProductAttributeValuePortal
{
   public virtual int ID { get; set; }
   public virtual Domain.Entity.Portals.ProductPortal Product { get; set; }
   public virtual Attribute Attribute { get; set; }
   public virtual string Value { get; set; }

}

with this very simple map

    public ProductAttributeValueMap ()
    {
        Table("DM.dbo.ProductAttributeValues");
        Id(x => x.ID, "ProductAttributeValue_id");
        References(x => x.Product);
        References(x => x.Attribute);
        Map(x => x.Value);
    }

Each time i make a insert NHibernate makes a Select of the attribute like :

    NHibernate: INSERT INTO MachineData.dbo.ProductAttributeValues (Value, Product_id,          
    Attribute_id) VALUES (@p0, @p1, @p2); select SCOPE_IDENTITY();@p0 = '6745', @p1 =  39, @p2 = 'BSTD'
    NHibernate: SELECT attribute_.Attribute_id, attribute_.Name as Name21_,   attribute_.AttributeType as Attribut3_21_, attribute_.TagName as TagName21_,   attribute_.MapTo as MapTo21_ FROM MachineShared.dbo.Attributes attribute_ WHERE   attribute_.Attribute_id=@p0;@p0 = 'DLB'

What am i doing wrong. And where do i find some really uptodate books about nhibernate/Fluent nhibernate