MDAC 2.5 SDK - ODBC Desktop Database Drivers
For the Paradox driver to update a table, the table must have a unique index (Paradox primary key). When you use the Paradox driver without implementing the Borland Database Engine, it is not possible to update a Paradox table.
Not supported by the Text driver.
When the Microsoft Excel driver is used, it is possible to update values, but a row cannot be deleted from a table based on a Microsoft Excel spreadsheet. As a result, the UPDATE statement is not considered officially supported by the Microsoft Excel driver. Only the INSERT statement is considered supported.