Beginning Oracle Database 11g Administration From Novice to Professional

CHAPTER 13 RECOVERY 285
Flashback Transaction
The SQL statements required to reverse changes can be automatically generated from
the undo segments. For example, an statement can be reversed with a
statement, and vice versa. All one needs to do is to select the necessary SQL statements
from the view—a DBA- level privilege called
is required. The transaction identifier () in the following example is the
one obtained in the previous section:
Flashback Table
All changes made to a table can be removed by using the command if the
information in the undo segments has not yet been overwritten by newer transactions.
For example, suppose that we inadvertently increased the salary of all employees, as in
the following example: