dbms

DBMS (default)

Autocommit processing is done by the DBMS Server and is subject to the restrictions mentioned above.

single

Single-cursor

The DAS allows only a single cursor to be open during autocommit. If a query or non-cursor operation is requested while a cursor is open, the server closes the open cursor. Any future attempts to access the cursor fails with an unknown cursor exception. This mode is useful for applications that fail to close result sets, but does not perform other queries or non-cursor related operations while the result set is being used.

multi

Multi-cursor

Autocommit processing is done by the DBMS Server when no cursors are open. The DAS disables autocommit and begins a standard transaction when a cursor is opened. Because autocommit processing is disabled, multiple cursors can be open at the same time and non-cursor operations are permitted.

When a cursor is closed, and no other cursor is open, the DAS commits the standard transaction and re-enables autocommit in the DBMS. This mode overcomes the restrictions imposed by the DBMS during autocommit, but requires the application to be very careful in closing result sets. Because the DAS does not commit the transaction until all cursors are closed, a cursor left open inadvertently eventually runs into log-file full problems and transaction aborts.