code: public void setLastModHint(Record record)
      {
          m_objLastModHint = null;
          for (m_iLastModType = DBConstants.MAIN_FIELD; m_iLastModType < record.getFieldCount() + DBConstants.MAIN_FIELD; m_iLastModType++)
          {
              BaseField field = record.getField(m_iLastModType);
              if (field.isModified()) if (!(field instanceof CounterField))
              {
                  m_objLastModHint = field.getData();
                  return;   // iFieldSeq = field
              }
          }
          m_iLastModType = -1;    // Not found
      }
docs: Optionally set a hint to be used to find the last modified record.
  This method is only called immediately before adding the physical record to the table.
  The default logic saves the first field it finds that is modified,
  since this is the field that would have triped the add logic.
  NOTE: This is a last resort, try to override getLastModified and use a DB Specific call.