Flashback [Oracle]

With Oracle's flashback, it's possible to sort of travel back in time. That is, flashback provides a means to see data that was altered through DDL operations and the state of database objects that were changed with DML operations. Oracle subcategorises flashback into three categories:

• Flashback query
  Get previous data with the as of clause of a select statement. See Flashback query example 1.
• Flashback version query
  Get changes of data between a time interval using the versions between clause of a select statement. See Flashback version query example 1.
• Flashback transaction query
  Find changes of a specific transaction through the flashback_transaction_query view. See Flashback transaction version query example 1.
• Flashback Table
• Flashback drop
  Undrops a dropped table.
• flashback database

In order to make flashback possible, Oracle uses undo.