Note: I was trying to do the same thing with a MySQL Database. You can run the following:
SET FOREIGN_KEY_CHECKS=0;
TRUNCATE TABLE `OrderNote`;
TRUNCATE TABLE `GiftCard`;
TRUNCATE TABLE `giftcardusagehistory`;
TRUNCATE TABLE `OrderItem`;
TRUNCATE TABLE `order`;
TRUNCATE TABLE `RewardPointsHistory`;
SET FOREIGN_KEY_CHECKS=1;
Thanks for this, it helped me!
Some of the table names were incorrect though (upper/lower case), here are the correct ones:
TRUNCATE TABLE `GiftCardUsageHistory`;
TRUNCATE TABLE `Order`;
Hope that helps someone else again :-)