FIX: AppendOnly Snapshot Recordset Update() Causes Error

   Error: failure updating record.
   Invalid argument value
   State:S1009,Native:57,Origin:[Microsoft][ODBC Microsoft Access
   7.0 Driver]
					

CAUSE

A snapshot recordset relies on the cursor library for additions or updates to the database. If the cursor library is not loaded, the recordset becomes read-only and does not allow additions or updates. In this case, the recordset member variable m_bUpdatable is correctly set to FALSE, but due to a bug in MFC, if the recordset is opened appendOnly, m_bAppendable is still set to TRUE. AddNew() checks m_bAppendable and continues to process the addition. Eventually, Update() is called. Because the cursor library is not present, Update() calls CRecordset::ExecuteSetPosUpdate() to use SQLSetPos for performing the update. SQLSetPos fails and generates the error message.

If the appendOnly option is not specified for the snapshot, then both m_bUpdatable and m_bAppendable are set properly and the expected behavior occurs:

• This error message is displayed in the output window when AddNew() is called: "Recordset is read-only."
• A CDBException is thrown.