RERUN ALL THE COMMANDS FROM STEP 9

12. Rerun all the commands from Step 9.

P AR T III

Two-Minute Drill

Restore Dropped Tables from the Recycle Bin

• Dropped tables can be restored with FLASHBACK TABLE <table_name> TO

BEFORE DROP, if the space they occupy has not been reused.

• Flashback drop cannot function if the owning schema or the tablespace has

been dropped.

• Dependent indexes, triggers, and grants will also be restored, as will all

constraints except foreign key constraints.

• Dropped tables can be viewed, but you cannot perform DML or DDL against

them.

• Space occupied by dropped objects does not impact on quotas or trigger space

shortage alerts.

Perform Flashback Query

• Flashback Query relies on data in the undo segments.

• The AS OF clause must be used to give access to the pseudocolumns that

identify different versions of a row.

• The point to which the flashback should go can be specified as a timestamp or

an SCN.

Use Flashback Transaction

• The SELECT ANY TRANSACTION and FLASHBACK ANY TABLE privileges

must be granted to users who will use the flashback transaction facility.

• Transactions can be viewed in the FLASHBACK_TRANSACTION_QUERY

view, the UNDO_SQL column being a construction of a statement to reverse

the change.

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• A transaction flashback may not succeed, because of conflicts caused

(typically) by constraint violations.

Perform Flashback Table Operations

• A table flashback attempts to reverse all changes applied to one or more tables.

• The necessary changes, no matter over what time or how many tables, are

applied as one transaction.

• Row movement must be enabled on tables before attempting a table flashback.

Configure and Monitor Flashback Database and Perform

Flashback Database Operations

• A database flashback is functionally equivalent to an incomplete recovery.

• Flashback logs exist in the flash recovery area, and the flashback buffer exists

in the shared pool; both are automatically managed.

• A database flashback operation is accomplished in mount mode and

terminated with a RESETLOGS.

• Both flashback log files and redo log files are needed during a flashback. The

database must be running in archivelog mode.

Set Up and Use a Flashback Data Archive

• An archive exists in one or more tablespaces.

• Once a table is nominated for archiving, some DDL commands will no longer

be possible.

• The FBDA background process captures before-images of rows and saves them to

the archive, and purges the archive of data that has passed its retention period.

Self Test