①SQL> SELECT OBJECT_ID FROM DBA_OBJECTS WHERE OBJECT_NAME='T2012';
OBJECT_ID                                                
---------                                           
 57082     


②SQL> SELECT HEADER_BLOCK,BLOCKS FROM DBA_SEGMENTS WHERE SEGMENT_NAME = 'T2012';
HEADER_BLOCK   BLOCKS
-------------  --------
683              8

③SQL> SELECT DBMS_ROWID.rowid_block_number(ROWID)USED_BLOCK_NUMBER FROM SCOTT.T2012;
USED_BLOCK_NUMBER                                                
----------------
684      

④SQL> SHUTDOWN IMMEDIATE;

⑤SQL> STARTUP;

⑥SQL> SELECT BLOCK#,CLASS# FROM V$BH WHERE OBJD = '57082';
no data found

⑦SQL> SELECT * FROM SCOTT.T2012;
ID
-----
1

⑧SQL> SELECT BLOCK#,CLASS# FROM V$BH WHERE OBJD='57082';
BLOCK#    CLASS#
-------   ----------
686        1
684        1
687        1
685        1
688        1
683        4

⑨SQL> SELECT EMPTY_BLOCKS FROM DBA_TABLES WHERE TABLE_NAME='T2012';
EMPTY_BLOCKS
------------
3