When you purchase a smallcase, you would be placing CNC market orders with IOC validity.
CNC: Cash and Carry which is the order type for Delivery stocks
IOC: Immediate or Cancel Validity. So the order will either gets executed immediately or it will gets cancelled in case if the order isn't going through due to various reasons. This ensures the order is no longer valid once placed.
Other order types such as Limit order, Stop Loss, AMO aren't available for smallcases as of now.