In the MFC ODBC database classes, dynasets are recordsets with dynamic properties; they remain synchronized with the data source in certain ways. MFC dynasets (but not forward-only recordsets) require an ODBC driver with Level 2 API conformance. If the driver for your data source conforms to the Level 1 API set, you can still use both updateable and read-only snapshots and forward-only recordsets, but not dynasets. However, a Level 1 driver can support dynasets if it supports extended fetch and keyset-driven cursors.
In ODBC terminology, dynasets and snapshots are referred to as cursors. A cursor is a mechanism used for keeping track of its position in a recordset. For more information about driver requirements for dynasets, see Dynaset. For more information about cursors, see the SDK in the MSDN documentation.
For updateable recordsets, your ODBC driver must support either positioned update statements or the ::SQLSetPos ODBC API function. If both are supported, MFC uses ::SQLSetPos for efficiency. Alternatively, for snapshots, you can use the cursor library, which provides the required support for updateable snapshots (static cursors and positioned update statements).