anchor.diff:    FValue := aValue;
   end;
   
  -procedure TNullableInteger.Assign(aSource: TNullableInteger);
  +procedure TNullableInteger.Assign(const aSource: TNullableInteger);
   begin
     if not aSource.IsNull then
       Self.Value := aSource.Value
  
positive.code:   Self.Value:= aValue;
  end;
  
  procedure TNullableString.Assign(aSource: TNullableString);
  begin
    if not aSource.IsNull then
      Self.Value:= aSource.Value
  
negative.code:     constructor Create(); override; overload;
      constructor Create(aValue: Integer); overload;
  
      procedure Assign(const aSource : TNullableInteger); overload;
      procedure Assign(const aSourceField : TField); override; overload;
      procedure Assign(const aValue : String); override; overload;
      procedure Assign(const aValue : Variant); override; overload;
  
  