Transaction Control (TCL) commands

Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.

* COMMIT - save work done
* SAVEPOINT - identify a point in a transaction to which you can later roll back
* ROLLBACK - restore database to original since the last COMMIT
* SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use