17.08.07
查詢預定義表空間：
SQL> select TABLESPACE_NAME,CONTENTS from dba_tablespaces;
SQL> select FILE_NAME, TABLESPACE_NAME from dba_data_files;
SYSTEM 系統表
SYSAUX 系統輔助表，不斷變化
UNDOTBS1 撤銷表空間，放撤銷數據——修改之前的舊數據，是系統自動維護的（oracle 獨有）
TEMP 臨時表空間
USERS
EXAMPLE
數據字典/動態性能視圖
SQL> conn hr/hr
SQL> desc user_tables
SQL> select TABLE_NAME from user_tables;
SQL> desc user_views
SQL> select VIEW_NAME from user_views;
SQL> desc user_indexes
SQL> select INDEX_NAME, TABLE_NAME from user_indexes;
SQL> conn scott/tiger
SQL> select TABLE_NAME from user_tables; user_表示用戶自己的
SQL> select VIEW_NAME from user_views;
SQL> select INDEX_NAME, TABLE_NAME from user_indexes;
SQL> conn hr/hr
SQL> select count(*) from all_tables; all_表示的是有權限訪問的對象
SQL> conn scott/tiger
SQL> select count(*) from all_tables;
SQL> conn hr/hr
SQL> select count(*) from dba_tables;
SQL> conn scott/tiger
SQL> select count(*) from dba_tables;
SQL> desc v$instance
SQL> desc v$database
Dml語句只能刪除簡單視圖，無鏈接，運算等
以v$ 開頭的動態性能視圖
存儲管理
查詢預定義表空間：
SQL> select TABLESPACE_NAME,CONTENTS from dba_tablespaces;
SQL> select FILE_NAME, TABLESPACE_NAME from dba_data_files;
SYSTEM 系統表
SYSAUX 系統輔助表，不斷變化
UNDOTBS1 撤銷表空間，放撤銷數據——修改之前的舊數據，是系統自動維護的（oracle 獨有）
TEMP 臨時表空間
USERS
EXAMPLE
創建新表空間：
SQL> create tablespace tbs01 datafile ‘/u01/app/oracle/oradata/orcl/tbs01.dbf‘ SIZE 10M AUTOEXTEND ON NEXT 10M MAXSIZE 100M;
在指定的表空間中創建表：
SQL> create table t1 tablespace tbs01 as select * from dba_objects where 1=0;
SQL> select bytes, blocks, extents, tablespace_name from dba_segments where segment_name=‘T1‘;
SQL> insert into t1 select * from dba_objects;
SQL> select bytes, blocks, extents, tablespace_name from dba_segments where segment_name=‘T1‘;
SQL> select extent_id, bytes, blocks from dba_extents where segment_name=‘T1‘;
SQL> insert into t1 select * from t1;
SQL> insert into t1 select * from t1;
SQL> insert into t1 select * from t1;
SQL> select bytes, blocks, extents, tablespace_name from dba_segments where segment_name=‘T1‘;
SQL> select extent_id, bytes, blocks from dba_extents where segment_name=‘T1‘;
SQL> insert into t1 select * from t1; 空間不足，報錯
SQL> rollback;
SQL> select bytes, blocks, extents, tablespace_name from dba_segments where segment_name=‘T1‘; 空間不釋放
SQL> alter table t1 move; 釋放空間
只讀表空間：
SQL> alter tablespace tbs01 read only;
SQL> delete t1; 禁止dml
SQL> insert into t1 select * from t1; 禁止dml
SQL> create table t2 (x int) tablespace tbs01; 失敗
SQL> alter table t1 add (x int); 成功
SQL> update t1 set x=1; 失敗
SQL> drop table t1; 成功
dml和ddl的區別
改變表空間大小：
resize，autoextend，add datafile
刪除表空間：
SQL> drop tablespace tbs01 including contents and datafile;
17.08.07