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Cursor Behaviors

ODBC supports the ISO options for specifying the behavior of cursors by specifying their scrollability and sensitivity. These behaviors are specified by setting the SQL_ATTR_CURSOR_SCROLLABLE and SQL_ATTR_CURSOR_SENSITIVITY options on a call to SQLSetStmtAttr. The SQL Server Native Client ODBC driver implements these options by requesting server cursors with the following characteristics.

Cursor behavior settings

Server cursor characteristics requested

SQL_SCROLLABLE and SQL_SENSITIVE

Keyset-driven cursor and version-based optimistic concurrency

SQL_SCROLLABLE and SQL_INSENSITIVE

Static cursor and read-only concurrency

SQL_SCROLLABLE and SQL_UNSPECIFIED

Static cursor and read-only concurrency

SQL_NONSCROLLABLE and SQL_SENSITIVE

Forward-only cursor and version-based optimistic concurrency

SQL_NONSCROLLABLE and SQL_INSENSITIVE

Default result set (forward-only, read-only)

SQL_NONSCROLLABLE and SQL_UNSPECIFIED

Default result set (forward-only, read-only)

Version-based optimistic concurrency requires a timestamp column in the underlying table. If version-based optimistic concurrency control is requested on a table that does not have a timestamp column, the server uses values-based optimistic concurrency.

Scrollability

When SQL_ATTR_CURSOR_SCROLLABLE is set to SQL_SCROLLABLE, the cursor supports all the different values for the FetchOrientation parameter of SQLFetchScroll. When SQL_ATTR_CURSOR_SCROLLABLE is set to SQL_NONSCROLLABLE, the cursor only supports a FetchOrientation value of SQL_FETCH_NEXT.

Sensitivity

When SQL_ATTR_CURSOR_SENSITIVITY is set to SQL_SENSITIVE, the cursor reflects data modifications made by the current user or committed by other users. When SQL_ATTR_CURSOR_SENSITIVITY is set to SQL_INSENSITIVE, the cursor does not reflect data modifications.

See Also

Concepts