ODBC Driver Requirements for Dynasets

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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 updatable 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 the article Dynaset. For more information about cursors, see the ODBC SDK Programmer’s Reference on the MSDN Library CD.

****Note   ****For updatable 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 updatable snapshots (static cursors and positioned update statements).