You *might* be able to get the old data using a flashback query, eg
SQL> SELECT deptno, dname,
2 VERSIONS_STARTTIME
3 ,VERSIONS_XID
4 ,VERSIONS_OPERATION
5 FROM dept
6 VERSIONS BETWEEN
7 TIMESTAMP SYSTIMESTAMP - INTERVAL '20:00' MINUTE TO SECOND
8 AND SYSTIMESTAMP
9 WHERE deptno = 10;
DEPTNO DNAME VERSIONS_STARTTIME VERSIONS_XID V
---------- -------------- ------------------------ ---------------- -
10 UNKNOWN 03-SEP-08 11.53.45 PM 0200100060040000 U
10 MONEY GRABBERS 03-SEP-08 11.53.36 PM 0600050065040000 U
10 FINANCE 03-SEP-08 11.53.24 PM 09000D001D050000 U
10 BEAN COUNTERS 03-SEP-08 11.53.12 PM 01001A00EA030000 U
10 ACCOUNTING
The above data is a *single* row in the table that has been changed 5 times.
But this will depend on how much undo information you have available to you (a DBA setting). If the query does not work, then you'd need to look at auditing or flashback data archive to assist you *in future* (ie, it won't get you back the data you've already updated)