anchor.diff:      SetValue(VarToStr(aValue));
   end;
   
  +procedure TNullableStringRecord.Assign(const aSource: TNullableString);
  +begin
  +  if aSource.IsNull then
  +    SetNull
  +  else
  +    SetValue(aSource.Value);
  +end;
  +
   function TNullableStringRecord.AsVariant: Variant;
   begin
     if IsNull then
  
positive.code: 
  { TNullableStringRecord }
  
  procedure TNullableStringRecord.SetNull;
  begin
    IsNull:= true;
  end;
  
  procedure TNullableStringRecord.SetValue(const aValue: String);
  begin
    IsNull := false;
    Value:= aValue;
  end;
  
  procedure TNullableStringRecord.Assign(const aSource: TNullableStringRecord);
  begin
    IsNull := aSource.IsNull;
    Value := aSource.Value;
  end;
  
  procedure TNullableStringRecord.Assign(const aSourceField: TField; const aAllowBlankValue : boolean);
  
negative.code: 
  end;
  
  procedure TNullableIntegerRecord.Assign(const aSource: TNullableInteger);
  begin
    if aSource.IsNull then
      SetNull
    else
      SetValue(aSource.Value);
  end;
  
  function TNullableIntegerRecord.AsVariant: Variant;
  begin
    if IsNull then
  