Understanding Flashback Technology - OCP: Oracle Database 12c Administrator Certified Professional - page 351

■ Flashback Temporal Validity Query
■ Flashback Table
■ Flashback Data Archive
■ Flashback Database
For each of these options, we will discuss the requirements, capabilities, and limitations
in detail.
Describe the Flashback Technologies
Oracle Flashback technology consists of Oracle Database features that let you view data-
base objects as they were at a previous point in time or return objects to a prior state with-
out performing point-in-time media recovery. Flashback technology was first introduced in
Oracle Database 9 i . Since then, it has been steadily improved with each successive Oracle
release. In Oracle Database 12 c , it represents a mature and time-tested technology.
Flashback technology consists of a set of tools that allow users to recover from logical data
errors without resorting to a database recovery. However, Flashback can do much more.
Recycle Bin The Recycle Bin allows dropped objects to persist in the database, and the
Flashback Drop option allows the objects to be restored.
Flashback Query The Flashback Query option allows the user to query tables as they
looked at a specific point in the past.
Flashback Version Query The Flashback Version Query option allows the user to retrieve a
historical view of data as it changed over time. In other words, if a column had been updated
multiple times, Flashback Version Query could provide a list of each of the values and the
date and time that they were changed.
Flashback Transaction Query Flashback Transaction Query is a useful diagnostic tool
that allows the user to retrieve detailed transaction information for previously executed
transactions. It can run for a single transaction or for all transactions that occurred during
a specified time frame.
Flashback Table Flashback Table allows point-in-time recovery (recovering one or more
tables to a specified point in the past) without the need to take any part of the database offline.
This offers a very desirable alternative to performing a full-blown point-in-time recovery.
Flashback Database Flashback Database is best used as a replacement for incomplete recov-
ery of the entire database. The main benefit of Oracle Flashback Database over incomplete
database recovery is that Flashback Database is much quicker and more efficient. Flashback
Database is not based on undo data but on flashback logs. It is best suited to recovering from
errors such as truncating a large table, an incomplete batch job, or a dropped user.
As you can see, Flashback offers a wide variety of tools for the DBA. However, these
options are not exclusive to the DBA. In fact, one of the key advantages to the various