SQL> select * from cdr;                                                          

    CDR_ID CONNECT_E USER_ID
---------- --------- --------------------
        19 20-APR-09 frankpachot
        20 20-MAY-09 michelcadot

SQL> truncate cdr;                                                               
truncate cdr
           *
ERROR at line 1:
ORA-03290: Invalid truncate command - missing CLUSTER or TABLE keyword


SQL> truncate table cdr;                                                         

Table truncated.

SQL> exit

SQL> ALTER SESSION SET NLS_TIMESTAMP_FORMAT = 'DD-MON-YYYY HH24:MI:SS.FF3';      

Session altered.

SELECT SYSTIMESTAMP,      LOCALTIMESTAMP    ,      DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER AS scnS scn
  2    FROM   dual;                                                              

SYSTIMESTAMP
---------------------------------------------------------------------------
LOCALTIMESTAMP
---------------------------------------------------------------------------
       SCN
----------
20-MAY-09 12.07.58.290886 AM +08:00
20-MAY-2009 00:07:58.290
    712077

SYSTIMESTAMP
---------------------------------------------------------------------------
LOCALTIMESTAMP
---------------------------------------------------------------------------
       SCN
----------
20-MAY-09 12.13.06.015679 AM +08:00
20-MAY-2009 00:13:06.015
    712271

Here's what I did in RMAN

RUN
{ 
    SET UNTIL SCN 712077;    
  # Alternatives:
  # SET UNTIL TIME 'Nov 15 2004 09:00:00';
  # SET UNTIL SEQUENCE 9923;  
  RESTORE DATABASE;
  RECOVER DATABASE;
9> }                                                                             

executing command: SET until clause

Starting restore at 20-MAY-09
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=156 devtype=DISK

channel ORA_DISK_1: restoring datafile 00001
input datafile copy recid=12 stamp=687233181 filename=/u01/app/oracle/flash_recov
.....

archive log filename=/u01/app/oracle/flash_recovery_area/TOMKYTE/archivelog/2009_05_19/o1_mf_1_30_515nml6w_.arc thread=1 sequence=30
media recovery complete, elapsed time: 00:00:06
Finished recover at 20-MAY-09

RMAN> ALTER DATABASE OPEN RESETLOGS;

database opened

RMAN> list INC
INCARNATION  INCLUDE      INCLUDING    INCREMENTAL  
RMAN> list INC
INCARNATION  INCLUDE      INCLUDING    INCREMENTAL  
RMAN> list INCARNATION ;                                                         


List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            STATUS  Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       1       TOMKYTE  3946756354       PARENT  1          30-JUN-05
2       2       TOMKYTE  3946756354       PARENT  446075     10-MAY-09
3       3       TOMKYTE  3946756354       PARENT  710178     19-MAY-09
4       4       TOMKYTE  3946756354       CURRENT 712090     20-MAY-09
 

SQL> select * from cdr;                                                          

    CDR_ID CONNECT_E USER_ID
---------- --------- --------------------
        19 20-APR-09 frankpachot
        20 20-MAY-09 michelcadot

SQL>