Column values are modified by calling the appropriate setType or AppendType method(s). The first append on a column clears
the current column value prior to appending the new value.
The data in the row is not actually changed until you call Update(), and that change is not made permanent until it is committed.
Modifying columns in the index used to open the table affects any active searches in unpredictable ways. Columns in the primary
key of the table can not be updated.