ASP.NET

SmartPhoneBaseID    (Identity Primary Key)
Company
PhoneName
RAM
Storage

SamsungPhoneID    (Identity Primary Kay)
SmartPhoneBaseID  (Foreign Key to dbo.SmartPhoneBase)
AndroidVersion
QualcommProcessorTech
AMOLEDDisplayTech

public class SmartPhoneBase
    {
        public virtual int SmartPhoneBaseID { get; private set; }

        public virtual string Company { get; set; }

        public virtual string PhoneName { get; set; }

        public virtual string RAM { get; set; }

        public virtual string Storage { get; set; }
    }

public class SamsungPhone:SmartPhoneBase
    {
        public virtual string AndroidVersion { get; set; }

        public virtual string QualcommProcessorTech { get; set; }

        public virtual string AMOLEDDisplayTech { get; set; }
    }

public class SmartPhoneBaseMap:ClassMap<SmartPhoneBase>
    {
        public SmartPhoneBaseMap()
        {
            Schema("dbo");
            Table("SmartPhoneBase");

            Id(x => x.SmartPhoneBaseID)
                .Column("SmartPhoneBaseID")
                .GeneratedBy.Identity();

            Map(x => x.Company).Length(100).Not.Nullable();
            Map(x => x.PhoneName).Length(100).Not.Nullable();
            Map(x => x.RAM).Length(100).Not.Nullable();
            Map(x => x.Storage).Length(100).Not.Nullable();
        }
    }

public class SamsungPhoneMap:SubclassMap<SamsungPhone>
    {
        public SamsungPhoneMap()
        {
            Schema("dbo");
            Table("SamsungPhone");

            Map(x => x.AndroidVersion).Length(100).Not.Nullable();
            Map(x => x.QualcommProcessorTech).Length(100).Not.Nullable();
            Map(x => x.AMOLEDDisplayTech).Length(100).Not.Nullable();
        }
    }

var result = nhSession.QueryOver<SmartPhoneBase>().List();

Invalid column name 'SmartPhoneBase_id'.
Invalid column name 'SmartPhoneBase_id'.