Transactions in Teradata Mode can be started and ended explicitly. Transactions in ANSI mode are always implicit. Transactions in ANSI mode start with the first SQL statement executed in a session or the first request executed after a previous transaction. ANSI mode transactions end when a COMMIT statement is executed, or a ROLLBACK or ABORT occurs. As you can see, no explicit BEGIN TRANSACTION is executed in ANSI mode, and each transaction ends (if there is no error) with a COMMIT statement. In Teradata Mode, a distinction is made between explicit transactions and implicit transactions. Explicit transactions are limited by BEGIN TRANSACTION and END TRANSACTION: BEGIN TRANSACTION; DELETE FROM Customer; UPDATE Sale SET Price = Price + 1; END TRANSACTION; If no explicit transaction is defined in Teradata mode, each request is an implicit transaction.