This has been a very useful improvement given
the ever-increasing size of today??™s databases.
However, this tablespace feature needs to be used carefully, since objects in one
tablespace may have dependencies, such as referential integrity constraints, on
objects in other tablespaces. For example, suppose that Tablespace1 contains the
EMP table and Tablespace2 contains the DEPT table, and a foreign key constraint
links these two tables together for referential integrity. If youwere to recover
Tablespace2 to an earlier point than Tablespace1, youmight find that youhad rows
in the EMP table that contained an invalid foreign key value, since the matching primary
key entry in the DEPT table had not been rolled forward to the place where the
primary key value to which the EMP table refers had been added. The newer Flashback
capability (described in the next section), particularly the Flashback Table
feature, now provides an easier-to-use alternative for table recovery.
Flashback
Oracle9i introduced a recovery approach called Flashback, which was designed to
help in recovering from user errors.
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