<b>Oracle Data block 的物理构造-体系架构</b>[Oracle防范]

SQL> create table t9 (a varchar(10));

Table created.

SQL> insert into t9 values('a');

1 row created.

SQL> commit;

Commit complete.

SQL> set serveroutput on
SQL> exec show_space('T9');
Free Blocks.............................1
Total Blocks............................8
Total Bytes.............................65536
Unused Blocks...........................6
Unused Bytes............................49152
Last Used Ext FileId....................3
Last Used Ext BlockId...................121
Last Used Block.........................2

PL/SQL procedure successfully completed.

SQL> alter system dump datafile 3 block 122;

System altered.

SQL> select * from v$tablespace;

       TS# NAME                           INC
---------- ------------------------------ ---
         0 SYSTEM                         YES
         1 UNDOTBS1                       YES
         8 USERS                          YES
        18 TEMP1