Flash Back Corrections
The retention value can be viewed from the
RETENTION
column of dba_tablespaces. The
possible values are GUARANTEE,
the
default which is NO GUARANTEE
Oracle Database 10g has come up with new
SQL functions to convert an SCN data type number
to a corresponding TIMESTAMP value and vice versa. This function
is useful in flashback operations
and
will be explained
in more detail
later.
The SCN_TO_TIMESTAMP
function will convert SCN to the
corresponding TIMESTAMP value while TIMESTAMP_TO_SCN
function
will convert a string representing a TIMESTAMP data type
to the corresponding SCN value of the NUMBER data type.
Flashback Transaction Query
One of the important new features of Oracle
Database 10g is the Flashback Transaction Query. It is a
diagnostic tool to view the changes made to the database at the
transaction level. This feature will help diagnose problems,
analyze and audit transactions, and recover from user or
application errors. The undo SQL generated by the flashback
transaction query can be used to rollback the changes made by a
transaction.
Flashback Transaction Query uses an indexed
access path to get to the undo data. It is faster than the
LogMiner, which mines the redo log files to obtain the undo
information.
