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).