18.5 Atomic Transactions
By default, a newly created database
Connection object is in auto-commit mode. That
means that each update to the database is treated as a separate
transaction and is automatically committed to the database.
Sometimes, however, you want to group several updates into a single
atomic transaction, with the property that either all the updates
complete successfully or no updates occur at all. With a database
system (and JDBC driver) that supports it, you can take the
Connection out of auto-commit mode and explicitly
call commit( ) to commit a batch of transactions
or call rollback( ) to abort a batch of
transactions, undoing the ones that have already been done. Example 21-3 in Chapter 21 uses atomic
transactions to ensure database consistency.