Devart Forums

Posted: **Wed 12 Oct 2011 08:28**

Hi Devart,
I currently changed datatype in one table from smallint to int, changed nothing in sources, the exe runs. BUT: the shown values are corrupted! for example, if the table contains value 666666, the exe shows 11306.
I know, I need to change TSmallintField to TIntegerField. But, I think, the sdac should somehow warn/raise an exception, i find this EXTREMELY dangerous for data validity!

Please help me, how could i avoid the data corruption. The source has >1000000 lines of code and about 100 columns have been changed (typically foreign keys)

Thanks, Ludek.

Posted: **Wed 12 Oct 2011 09:34**

solved myself, in custom subclass overriden a protected virtual method

Code: Select all

procedure TMyMSQuery.CheckFieldCompatibility(Field: TField;
  FieldDef: TFieldDef);
begin
  if (field.datatype = ftSmallint) and (fielddef.datatype = ftInteger) then
    DatabaseErrorFmt(SFieldTypeMismatch, [field.DisplayName,
      FieldTypeNames[field.DataType], FieldTypeNames[FieldDef.DataType]], Self)
  else
    inherited;
end;

and using one hack (see Hallvard's blog) also replaced the same VMT item directly in TMSQuery. Now I'm getting the errors.

Posted: **Fri 14 Oct 2011 08:45**

SDAC dataset components inherit fields compatibility checking from the TDataSet component. You can use your way to receive errors in this case.

Devart Forums

column datatype changed, no error in app, but corrupted data

column datatype changed, no error in app, but corrupted data