One to One Relationship Issue - Creating Records

Hi.

I have an odd error, I have two tables X and Y, there is a one to one relationship between them. X has an PK which is an auto increment ID called XID. Y has a PK which is also a FK to table X, this PK is also called XID. I can create a record in X no problem, but when I create a record in Y using the XID from X it fails.

The basic code is:

var x = new X();
uow.Add(x);
uow.SaveChanges();

x.Id (XID) now has a value.

var y = new Y();
y.X = x;
uow.Add(y);
uow.SaveChanges();

At this point I get an exception "An error occurred when trying to assign a new Identity value to this entity. Check inner exception for details", with and inner exception of "Object cannot be cast from DBNull to other types."

I have included a raw dump of the exception...

Mindscape.LightSpeed.LightSpeedException was caught
  HResult=-2146233088
  Message=An error occurred when trying to assign a new Identity value to this entity. Check inner exception for details
  Source=Mindscape.LightSpeed
  StackTrace:
       at Mindscape.LightSpeed.LightSpeedException. (Exception , String , Object[] )
       at Mindscape.LightSpeed.Entity`1.SetIdInternal(Object )
       at  . . (Entity ,   )
       at  . . (Entity , ICollection`1 )
       at  . . (Entity , List`1 )
       at  . . (UnitOfWorkBase , IEnumerable`1 , IEnumerable`1 )
       at Mindscape.LightSpeed.UnitOfWork.SaveChanges(Boolean reset)
       at RedStarCreative.TradeGuideGroup2011.Models.DvlaLookup.UpdateValues(Int32 valuationId) in z:\Projects\RedStarCreative.TradeGuideGroup2011\trunk\RedStarCreative.TradeGuideGroup2011.Models\DvlaLookup.cs:line 765
  InnerException: System.InvalidCastException
       HResult=-2147467262
       Message=Object cannot be cast from DBNull to other types.
       Source=mscorlib
       StackTrace:
            at System.DBNull.System.IConvertible.ToInt32(IFormatProvider provider)
            at System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider)
            at Mindscape.LightSpeed.Entity`1.SetIdInternal(Object )
       InnerException: 

Thanks in advance for your support.

What identity strategy are you using for Y? You could try overriding Entity.GenerateId on Y to control Id assignment but in general this type of mapping is going to have issues as this is not supported by LightSpeed, we expect the PK and FK to be distinct fields.

Jeremy