Every time you create a new application or update a table
in an application that requires historical tracking, you must make changes to your tracking
application as well. As of Oracle Database 11g, you can use Flashback Data Archive to
automatically save historical changes to all key tables for as long as regulatory agencies or
your stakeholders require.
Flashback Data Archive is implemented natively in Oracle Database 11g; in a nutshell, you
create one or more repository areas (one of which can be the default), assign a default retention
period for objects in the repository, and then mark the appropriate tables for tracking.
A Flashback Data Archive acts much like an undo tablespace; however, a Flashback Data
Archive only records update and delete statements, but not insert statements. In addition, undo
data is typically retained for a period of hours or days for all objects; rows in Flashback Data
Archives can span years or even decades. Flashback Data Archives has a much narrower focus as
well, recording only historical changes to table rows; Oracle uses data in an undo tablespace for
read-consistency in long-running transactions and to roll back uncommitted transactions.
You can access data in a Flashback Data Archive just as you do with Flashback Query: using
the as of clause in a select statement. In the next few sections, we??™ll show you how to create a
Flashback Data Archive, assign permissions to users and objects, and query historical data in
a Flashback Data Archive.
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