I ran into a bit of confusion. I'm under the belief that database operations are automatic – that is either the query succeeds or the transaction is automatically rolledback. For example – if you have a long running UPDATE statement and you "cancel" it before it finishes – IE clicking red circle X button in SQL Developer (which you should receive a ORA-01013: user requested cancel of current operation error). Upon canceling the query the query is rolled back and no rows were affected. I believe the same should hold true for DELETE statements.
I looked around for some documentation on it and I found this article that really isn't authoritative.
Best Answer
If you do that, the statement is rolled back, not the transaction. Below I hit Ctrl+C after starting the UPDATE.
1 transaction was rolled back and 173323 undo records were applied to perform the rollback. But that is because I had no other change in that transaction.
If I have other changes in the transaction, those changes will not be rolled back automatically:
Notice how the value of transaction rollbacks remained 0 this time, and how the INSERT was not rolled back, and I was still able to rollback the transaction manually.