6.7. Summary
In this chapter, you learned about the Flashback Technologies in detail. The Flashback Technologies consist of the Flashback Drop, Flashback Versions Query, Flashback Transaction Query, and Flashback Table.
Flashback Query was first developed in Oracle 9i and is the basis for the rest of the Flashback Technologies developed in Oracle 10g. We discussed the Recycle Bin in detail, and you learned how to
Drop tables to the Recycle Bin
Query the Recycle Bin
Recover tables from the Recycle Bin
Permanently remove objects from the Recycle Bin and deallocate the space allocated to them
You also learned how Flashback Drop works with the Recycle Bin and that when space pressure arises, Oracle automatically reclaims space by overwriting objects in the Recycle Bin.
The next section discussed and provided hand-on examples of using the Flashback Versions Query. This capability retrieves all versions of the rows that exist or existed between the times the query was executed to a determined point-in-time in the past. Flashback Versions Query works by retrieving data from the UNDO tablespace and uses either SCNs or timestamps to identify the start and stop points.
You then used the Flashback Transaction Query to diagnose and analyze transactional changes in data. You saw examples of how you can use this tool to perform transactional analysis using transaction identifiers or timestamps.
The last Flashback Technology discussed in this chapter was the Flashback Table. You use Flashback Table to recover a table or to set tables to a specific point-in-time without performing an incomplete recovery. All dependent objects are also recovered when using Flashback Table. Flashback Table has numerous benefits over incomplete recovery.
EM also can perform Flashback Technologies and you walked through performing a Flashback Table recovery within EM.