Oracle strongly recommends that you run your database in automatic undo mode by leaving
the UNDO_MANAGEMENT initialization parameter set to AUTO, which is the default. In addition,
set the UNDO_RETENTION initialization parameter to an interval large enough to include the
oldest data you anticipate needing.
For more information refer to the documentation on the UNDO_MANAGEMENT and UNDO_RETENTION
initialization parameters in ORACLE docs.
There are multiple methods to flashback a table in Oracle database. You do not need to
enable this flashback feature, it comes by default.
Note: TO FLASHBACK a table to its original, you will have to enable row movement.
ALTER TABLE TABLE_NAME ENABLE ROW MOVEMENT.
1. If you have dropped a table accidentally, we can flashback the table.
2. To rename table on the fly when you flashback.
3. Flashback table to its original table with interval in MINUTES.
4. Flashback table to its original table with TIMESTAMP.
5. If you have passed the UNDO RETENTION period, there are chances to still flashback a table. Verify if you can flashback:
If you see the result, you will be able to flashback else you will not be able to flashback.
6. Create a new table with flashback data.
7. Check the versions of flashback content.