A transaction is defined as a set of independent operations that are performed as an atomic operation, meaning that the operations succeed or fail as a whole. Because a transaction is defined as a single unit of work, they can also be committed or rolled back. TransactionLock method initiate transactions and transaction ends with Unlock method. All methods between these two methods belongs to the transaction and can be committed or rolled back (aborted) depends on what you specified as parameter in Unlock method.