[Oracle 10g]-關(guān)于表空間的更名
2024-08-29 13:37:41
供稿：網(wǎng)友
簡(jiǎn)單介紹
在 Oracle 10g 以前的版本，更改表空間名字是幾乎不可能的事情，除非刪除，重新創(chuàng)建，大費(fèi)周章。Oracle 10g 新添加了一項(xiàng)更改表空間名字的功能，使得更改表空間名字瞬間即可完成。是個(gè)較為人性化的功能。
SQL> COL FILE_NAME format a70
SQL> SET linesize 120
SQL> SET pagesize 99
SQL> COL TABLESPACE_NAME format a10
SQL>
SQL> SELECT file_name, tablespace_name FROM dba_data_files;
FILE_NAME TABLESPACE
---------------------------------------------------------------------- ----------
/u01/app/oracle/PRodUCt/10.1.0/db_1/oradata/TEST/users01.dbf USERS
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf SYSAUX
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf UNDOTBS1
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf SYSTEM
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf EXAMPLE
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf FOO
6 rows selected.
該命令的語(yǔ)法很簡(jiǎn)單:
ALTER TABLESPACE tablespacename RENAME TO newtablespacename;
tablespacename 和newtablespacename 分別對(duì)應(yīng)原來的表空間名字和更改后的表空間名字：
實(shí)戰(zhàn)演練
注重：在操作前后都請(qǐng)做好控制文件的備份工作
SQL>ALTER TABLESPACE foo RENAME TO test;
Tablespace altered.
SQL> SELECT file_name, tablespace_name FROM dba_data_files;
FILE_NAME TABLESPACE
---------------------------------------------------------------------- ----------
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/users01.dbf USERS
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf SYSAUX
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf UNDOTBS1
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf SYSTEM
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf EXAMPLE
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf TEST
因?yàn)?system 和 sysaux 這兩個(gè)表空間的非凡性，是不可以更名的:
SQL> ALTER TABLESPACE system RENAME TO mysystem;
ALTER TABLESPACE system RENAME TO mysystem
*
ERROR at line 1:
ORA-00712: cannot rename system tablespace
SQL> ALTER TABLESPACE sysaux RENAME TO mysysaux;
ALTER TABLESPACE sysaux RENAME TO mysysaux
*
ERROR at line 1:
ORA-13502: Cannot rename SYSAUX tablespace
可以對(duì) undo tablespace 重新命名，假如使用的是 spfile ,而不是 pfile, Oracle 會(huì)自動(dòng)對(duì) spfile 中的 undo_tablespace 進(jìn)行更改(不過要在數(shù)據(jù)庫(kù)重新啟動(dòng)之后才可以觀察到), 假如使用的是 pfile ,要對(duì)其進(jìn)行手工更改。我們看看 spfile 的變化情況：
SQL> ALTER tablespace undotbs1 RENAME TO undotbs;
Tablespace altered.
SQL>
SQL> show parameter pfile
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string /u01/app/oracle/product/10.1.0
/db_1/dbs/spfileTEST.ora
SQL> show parameters undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 180355072 bytes
Fixed Size 777996 bytes
Variable Size 128983284 bytes
Database Buffers 50331648 bytes
Redo Buffers 262144 bytes
Database mounted.
Database opened.
SQL> show parameters undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS
SQL>
對(duì)脫機(jī)表空間的更名是不答應(yīng)的：
SQL> ALTER TABLESPACE TEST OFFLINE;
Tablespace altered.
SQL> ALTER TABLESPACE test RENAME TO testoffline;
ALTER TABLESPACE test RENAME TO testoffline
*
ERROR at line 1:
ORA-01135: file 6 accessed for DML/query is offline
ORA-01110: data file 6:
'/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf'
給出的提示信息很有參考價(jià)值：更名操作是要對(duì)表空間進(jìn)行 DML/query 操作的，表空間offline的話，則不可以。
那么假如表空間是只讀的會(huì)怎么樣呢？
SQL> ALTER TABLESPACE TEST ONLINE;
Tablespace altered.
SQL> ALTER TABLESPACE TEST READ ONLY;
Tablespace altered.
SQL> ALTER TABLESPACE test RENAME TO testreadonly;
Tablespace altered.
SQL> list
1* SELECT file_name, tablespace_name FROM dba_data_files
SQL> /
FILE_NAME TABLESPACE
---------------------------------------------------------------------- ----------
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/users01.dbf USERS
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf SYSAUX
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf UNDOTBS
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf SYSTEM
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf EXAMPLE
/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf TESTREADONLY
6 rows selected.
SQL>
看來數(shù)據(jù)字典已經(jīng)更新，不過Oracle會(huì)向alert_SID.log 中寫入類似如下的日志:
ALTER TABLESPACE test RENAME TO testreadonly
Sat Nov 13 16:15:21 2004
Tablespace 'TEST' is renamed to 'TESTREADONLY'.
Tablespace name change is not propagated to file headersbecause the tablespace is read only.
Completed: ALTER TABLESPACE test RENAME TO testreadonly
注重Log里有個(gè)細(xì)微的小Bug：headersbecause。這是兩個(gè)詞，應(yīng)該空開的 :-)
限制條件
應(yīng)用這個(gè)特性有個(gè)主要的限制條件：COMPATIBLE 初始化參數(shù)要求為 10.0 或者更高才可以
