Sets the deferred database slave lock if the VORTEXaccelerator is active.
If the VORTEXaccelerator is active, then db_mux() sets the
deferred database slave lock flag, which locks the slave to
the client on the following database operation.
You need to execute a COMMIT/ROLLBACK to free the slave.
Locks the VORTEXaccelerator to the client to prevent a potential deadlock.
ll = list_open("select * from staff for update of id,salary",100);
exec_sql("update staff set salary = salary * .60
where id = :1",list_curr(ll,0));