Microsoft® SQL Server 2012 Unleashed

Implicit Transactions

AutoCommit transactions and explicit user-defined transactions, which are the default transaction mode in SQL Server 2012, are not ANSI-92 SQL-compliant. The ANSI-92 SQL standard states that any data retrieval or modification statement issued should implicitly begin a multistatement transaction that remains in effect until an explicit ROLLBACK or COMMIT statement is issued. Microsoft refers to this transaction mode as IMPLICIT_TRANSACTIONS.

To enable implicit transactions for a connection in SQL Server 2012, you need to enable the IMPLICIT_TRANSACTIONS session setting using the following command:

SET IMPLICIT_TRANSACTIONS ON

After this option is turned on, transactions are implicitly started, if they are not already in progress, ...