select log_mode from v$database; LOG_MODE ..."/>
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一、配置閃回?cái)?shù)據(jù)庫
1、數(shù)據(jù)庫處于歸檔日志模式
SQL> select log_mode from v$database;
LOG_MODE
------------
ARCHIVELOG
2、創(chuàng)建閃回恢復(fù)區(qū)
SQL> alter system set db_recovery_file_dest_size=10G;
System altered.
SQL> alter system set db_recovery_file_dest='D:\oracle\product\11.2.0\dbhome_1\RDBMS';
System altered.
3、設(shè)置閃回保留目標(biāo)時(shí)間
SQL> alter system set db_flashback_retention_target=240;
System altered.
--DB_FLASHBACK_RETENTION_TARGET參數(shù)控制保留時(shí)間,單位是分鐘,默認(rèn)值是1天。閃回日志空間以循環(huán)的方式重用,更新的數(shù)據(jù)將覆蓋舊的數(shù)據(jù)。(本例為保留4小時(shí))
4、關(guān)閉數(shù)據(jù)庫并啟動(dòng)到MOUNT狀態(tài)
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 3373858816 bytes
Fixed Size 2180424 bytes
Variable Size 1845496504 bytes
Database Buffers 1509949440 bytes
Redo Buffers 16232448 bytes
Database mounted.
5、啟用閃回日志記錄并打開數(shù)據(jù)庫
SQL> alter database flashback on;
Database altered.
SQL> alter database open;
Database altered.
6、查看是否啟用閃回日志記錄
SQL> select flashback_on from v$database;
FLASHBACK_ON
------------------
YES
二、使用sqlplus閃回?cái)?shù)據(jù)庫
1、創(chuàng)建一個(gè)臨時(shí)表
SQL> create table t as select * from dba_objects;
Table created.
2、查詢當(dāng)前系統(tǒng)時(shí)間表
SQL> select to_char(sysdate,'yyyy-mm-dd hh34:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2016-03-15 11:34:21
3、對(duì)t表做一些DML操作
SQL> delete from t;
72464 rows deleted.
SQL> commit;
Commit complete.
SQL> insert into t select * from dba_objects where rownum<=100;
100 rows created.
SQL> commit;
Commit complete.
SQL> select count(*) from t;
COUNT(*)
----------
100
4、把數(shù)據(jù)庫閃回到步驟2查詢出的時(shí)間
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 3373858816 bytes
Fixed Size 2180424 bytes
Variable Size 1845496504 bytes
Database Buffers 1509949440 bytes
Redo Buffers 16232448 bytes
Database mounted.
SQL> flashback database to timestamp to_timestamp('2016-03-15 11:34:21','yyyy-mm-dd hh34:mi:ss');--可以接受時(shí)間戳或系統(tǒng)變更號(hào)(SCN)參數(shù),不接受日期或日志世界的序列號(hào)
Flashback complete.
5、以只讀方式打開數(shù)據(jù)庫查詢是否閃回成功 --注意使用read only方式打開數(shù)據(jù)庫,驗(yàn)證閃回情況。
SQL> alter database open read only;
Database altered.
SQL> select count(*) from t;
COUNT(*)
----------
72464
6、閃回成功后,以resetlogs方式打開數(shù)據(jù)庫
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 3373858816 bytes
Fixed Size 2180424 bytes
Variable Size 1845496504 bytes
Database Buffers 1509949440 bytes
Redo Buffers 16232448 bytes
Database mounted.
SQL> alter database open resetlogs;
Database altered.
SQL> select count(*) from t;
COUNT(*)
----------
72464
數(shù)據(jù)庫閃回成功
注:如果flashback閃回的數(shù)據(jù)庫時(shí)間太早,可以使用RECOVER DATABASE UNTILE TIME times恢復(fù)到后邊的時(shí)間點(diǎn)。
--也可以使用RMAN進(jìn)行閃回
RMAN>flashback database to time = to_date('2016-03-15 11:34:21','yyyy-mm-dd hh34:mi:ss');
RMAN>flashback database to scn = 2728665;
RMAN>flash backup to sequence = 2123 thread = 1;
三、限制生成的閃回?cái)?shù)據(jù)量
1、關(guān)閉表空間閃回屬性
ALTER TABLESPACE tablespace_name FLASHBACK OFF;
2、開啟表空間閃回屬性
ALTER TABLESPACE tablespace_name FLASHBACK ON;--只能在mount狀態(tài)下執(zhí)行
3、查看表空間的閃回屬性
select name,flashback_on from v$tablespace;
四、設(shè)置sqlplus提示符
SQL> set sqlprompt "_user'@'_connect_identifier>"
SYS@ocp>
--為了對(duì)所有的sqlplus會(huì)話自動(dòng)設(shè)置sqlprompt。將上面的命令放置在ORACLE_HOME/sqlplus/admin目錄中的glogin.sql文件中
五、閃回刪除
1、創(chuàng)建一個(gè)練習(xí)用戶
SYS@ocp>create user dropper identified by dropper;
User created.
SYS@ocp>grant create session,resource to dropper;
Grant succeeded.
SYS@ocp>connect dropper/dropper;
Connected.
2、創(chuàng)建一個(gè)帶有索引和約束的表,并插入一行
DROPPER@ocp>create table names(name varchar2(10));
Table created.
DROPPER@ocp>create index name_idx on names(name);
Index created.
DROPPER@ocp>alter table names add constraint name_u unique (name);
Table altered.
DROPPER@ocp>insert into names values('John');
1 row created.
DROPPER@ocp>commit;
Commit complete.
3、確認(rèn)模式的內(nèi)容
DROPPER@ocp>select object_name,object_type from user_objects;
OBJECT_NAME OBJECT_TYPE
-------------------------------------
NAME_IDX INDEX
NAMES TABLE
DROPPER@ocp>select constraint_name,constraint_type,table_name from user_constraints;
CONSTRAINT_NAME C TABLE_NAME
------------------------------ - ------------------------------
NAME_U U NAMES
4、刪除該表
DROPPER@ocp>drop table names;
Table dropped.
5、查詢回收站查看原始名稱到回收站名稱的映射
DROPPER@ocp>select object_name,original_name,type from user_recyclebin;
OBJECT_NAME ORIGINAL_NAME TYPE
------------------------------ ------------------ -------------------------
BIN$q+6VgWdBRGOykqOJfCyZNg==$0 NAME_IDX INDEX
BIN$u1TeIIlLS3isIPDvpSTblQ==$0 NAMES TABLE
--注:視圖并沒有顯示約束
6、可以使用回收站的對(duì)象名進(jìn)行查詢,但不可做DML語句
DROPPER@ocp>select * from "BIN$u1TeIIlLS3isIPDvpSTblQ==$0";
NAME
----------
John
DROPPER@ocp>insert into "BIN$u1TeIIlLS3isIPDvpSTblQ==$0" values('Root');
insert into "BIN$u1TeIIlLS3isIPDvpSTblQ==$0" values('Root')
*
ERROR at line 1:
ORA-38301: can not perform DDL/DML over objects in Recycle Bin
7、使用FLASHBACK drop恢復(fù)表
DROPPER@ocp>flashback table names to before drop;
Flashback complete.
8、查詢模式中的內(nèi)容
DROPPER@ocp>select * from names;
NAME
----------
John
DROPPER@ocp>select object_name,original_name,type from user_recyclebin;
no rows selected
DROPPER@ocp>select object_name,object_type from user_objects;
OBJECT_NAME OBJECT_TYPE
-------------------------------------------------
BIN$q+6VgWdBRGOykqOJfCyZNg==$0 INDEX
NAMES TABLE
DROPPER@ocp>select constraint_name,constraint_type,table_name from user_constraints;
CONSTRAINT_NAME C TABLE_NAME
------------------------------ - ------------------------------
BIN$cLAR1tu9Toi3u5qKdAbvIw==$0 U NAMES
9、將索引和約束重命名回原先的名稱
DROPPER@ocp>alter index "BIN$q+6VgWdBRGOykqOJfCyZNg==$0" rename to name_idx;
Index altered.
DROPPER@ocp>alter table names rename constraint "BIN$cLAR1tu9Toi3u5qKdAbvIw==$0" to name_u;
Table altered.
DROPPER@ocp>select object_name,object_type from user_objects;
OBJECT_NAME OBJECT_TYPE
----------------------------------
NAME_IDX INDEX
NAMES TABLE
DROPPER@ocp>select constraint_name,constraint_type,table_name from user_constraints;
CONSTRAINT_NAME C TABLE_NAME
------------------------------ - ------------------------------
NAME_U U NAMES
10、使用SYS用戶刪除DROPPER模式
SYS@ocp>drop user dropper cascade;
User dropped.
11、查詢DBA_RECYCLEBIN視圖來證實(shí)確實(shí)刪除了用戶DROPPER擁有的所有對(duì)象。
SYS@ocp>select count(*) from dba_recyclebin where owner='DROPPER';
COUNT(*)
----------
0
注:如果回收站中兩兩個(gè)表的原始名稱相同,默認(rèn)情況下,Flashback Drop命令總是恢復(fù)最新版本的表,但如果不是想要的版本,可以指定希望恢復(fù)的版本的回收站名稱,而不是原先的名稱。
SQL>flashback table "BIN$q+6VgWdBRGOykqOJfCyZNg==$0" to before drop;
六、管理回收站
SQL>show recyclebin;
user_recyclebin
dba_recyclebin
注:Flashback Drop不適用于存儲(chǔ)在SYSTEM表空間中的表,直接將它們刪掉并清除了
永久清除刪掉的對(duì)象
DROP TABLE table_name PURGE;--刪除表并不將它轉(zhuǎn)移到回收站
PURGE TABLE table_name;--從回收站中清除表。如果存在多個(gè)具有相同原始名稱的對(duì)象,清除時(shí)間最久的對(duì)象。也可以通過指定回收站名稱來避免這種混淆。
PURGE INDEX index_name;--從回收站中消除索引。同樣可以指定原始名稱或回收站名稱。
PURGE TABLESPACE tablespace_name;--從表空間中清除所有刪除的對(duì)象。
PURGE TABLESPACE tablespace_name USER user_name;--從表空間中清除屬于一個(gè)用戶的所有刪除的對(duì)象。
PURGE USER_RECYCLEBIN;--清除用戶刪除文件的所有對(duì)象。
PURGE DBA_RECYCLEBIN;--清除所有刪除的對(duì)象,需要dba權(quán)限。
七、閃回查詢
--所有形式的閃回查詢依賴撤銷數(shù)據(jù)來重構(gòu)它在過去某個(gè)時(shí)間點(diǎn)的數(shù)據(jù)。
1、基本的閃回查詢
1.1創(chuàng)建測(cè)試表并插入測(cè)試數(shù)據(jù)
USER1@mydb>create table regions (region_id number,region_name varchar2(20));
Table created.
USER1@mydb>insert into regions values(1,'Europe');
1 row created.
USER1@mydb>insert into regions values(2,'Americas');
1 row created.
USER1@mydb>insert into regions values(3,'Asia');
1 row created.
USER1@mydb>insert into regions values(4,'Middle East');
1 row created.
USER1@mydb>commit;
Commit complete.
1.2查詢系統(tǒng)當(dāng)前時(shí)間,刪除部分?jǐn)?shù)據(jù)并確認(rèn)
USER1@mydb>select sysdate from dual;
SYSDATE
-------------------
2016-03-15 19:08:16
USER1@mydb>delete from regions where region_name like 'A%';
2 rows deleted.
USER1@mydb>commit;
Commit complete.
USER1@mydb>select * from regions;
REGION_ID REGION_NAME
---------- --------------------
1 Europe
4 Middle East
1.3進(jìn)行閃回查詢
USER1@mydb>select * from regions as of timestamp to_timestamp('2016-03-15 19:08:16','yyyy-mm-dd hh34:mi:ss');
REGION_ID REGION_NAME
---------- --------------------
1 Europe
2 Americas
3 Asia
4 Middle East
1.4查詢閃回時(shí)間點(diǎn)到現(xiàn)在的差異
USER1@mydb>select * from regions as of timestamp to_timestamp('2016-03-15 19:08:16','yyyy-mm-dd hh34:mi:ss') minus select * from regions;
REGION_ID REGION_NAME
---------- --------------------
2 Americas
3 Asia
可以使用DBMS_FLASHBACK程序包將整個(gè)會(huì)話回退到過去某個(gè)時(shí)間,對(duì)其他會(huì)話沒有影響。處于閃回模式中不支持DMS語句。
USER1@mydb>execute dbms_flashback.enable_at_time(to_timestamp('2016-03-15 19:08:16','yyyy-mm-dd hh34:mi:ss'));
PL/SQL procedure successfully completed.
USER1@mydb>select * from regions;
REGION_ID REGION_NAME
---------- --------------------
1 Europe
2 Americas
3 Asia
4 Middle East
USER1@mydb>execute dbms_flashback.disable;
PL/SQL procedure successfully completed.
select * from table_name as of timestamp(systimestamp-interval '30' minute);
select * from table_name as of timestamp(systimestamp-interval '1' hour);
2、閃回表查詢 --啟用表閃回的第一步是在表上支持行移動(dòng)。
2.1創(chuàng)建測(cè)試表插入測(cè)試數(shù)據(jù)
HR@mydb>create table dept (dept_id number,dept_name varchar2(20));
Table created.
HR@mydb>alter table dept add constraint pk_dept primary key (dept_id);
Table altered.
HR@mydb>create table emp (emp_id number,name varchar2(20),dept_id number);
Table created.
HR@mydb>alter table emp add constraint fk_emp foreign key (dept_id) references dept(dept_id);
Table altered.
HR@mydb>insert into dept values(1,'SUPPORT');
1 row created.
HR@mydb>select * from dept;
DEPT_ID DEPT_NAME
---------- --------------------
1 SUPPORT
HR@mydb>commit;
Commit complete.
HR@mydb>insert into emp values(101,'John',1);
1 row created.
HR@mydb>commit;
Commit complete.
HR@mydb>select * from emp;
EMP_ID NAME DEPT_ID
---------- -------------------- ----------
101 John 1
2.2、查看當(dāng)前系統(tǒng)時(shí)間
HR@mydb>select sysdate from dual;
SYSDATE
-------------------
2016-03-15 21:37:36
2.3、刪除測(cè)試表數(shù)據(jù)
HR@mydb>delete from emp where emp_id=101;
1 row deleted.
HR@mydb>delete from dept where dept_id=1;
1 row deleted.
HR@mydb>commit;
Commit complete.
2.4、開始閃回表
flashback table table_name to timestamp to_timestamp(systimestamp-interval '30' minute);
HR@mydb>flashback table emp to timestamp to_timestamp('2016-03-15 21:37:36','yyyy-mm-dd hh34:mi:ss');
flashback table emp to timestamp to_timestamp('2016-03-15 21:37:36','yyyy-mm-dd hh34:mi:ss')
*
ERROR at line 1:
ORA-08189: cannot flashback the table because row movement is not enabled
--提示需要打開表的row movement
HR@mydb>alter table emp enable row movement;
Table altered.
HR@mydb>alter table dept enable row movement;
Table altered.
HR@mydb>flashback table emp to timestamp to_timestamp('2016-03-15 21:37:36','yyyy-mm-dd hh34:mi:ss');
flashback table emp to timestamp to_timestamp('2016-03-15 21:37:36','yyyy-mm-dd hh34:mi:ss')
*
ERROR at line 1:
ORA-02091: transaction rolled back
ORA-02291: integrity constraint (HR.FK_EMP) violated - parent key not found
--提示有外鍵約束
--兩個(gè)表同時(shí)閃回避免約束問題
HR@mydb>flashback table emp,dept to timestamp to_timestamp('2016-03-15 21:37:36','yyyy-mm-dd hh34:mi:ss');
Flashback complete.
2.5、檢查閃回結(jié)果
HR@mydb>select * from dept;
DEPT_ID DEPT_NAME
---------- --------------------
1 SUPPORT
HR@mydb>select * from emp;
EMP_ID NAME DEPT_ID
---------- -------------------- ----------
101 John 1
--語法的變型允許閃回到一個(gè)系統(tǒng)變更號(hào)并在操作期間激活DML觸發(fā)器。
flashback table emp,dept to scn 6539425 enable triggers;
3、閃回版本查詢
--使用VERSIONS BETWEEN關(guān)鍵字
--根據(jù)scn的返回版本
select emp_id, versions_xid,versions_startscn,versions_endscn,versions_operation from emp versions between scn minvalue and maxvalue where emp_id=101;
--根據(jù)時(shí)間戳的返回版本
select emp_id, versions_xid,versions_starttime,versions_endtime,versions_operation from emp versions between timestamp (systimestamp - 25/1440) and systimestamp where emp_id=101;
4、閃回事務(wù)
--使用閃回事務(wù)需要開啟庫的最小附加日志 alter database add supplemental log data;
4.1創(chuàng)建測(cè)試表并插入數(shù)據(jù)
USER1@mydb>create table countries(name varchar2(10));
Table created.
USER1@mydb>alter table countries enable row movement;
Table altered.
USER1@mydb>insert into countries values('Zambia');
1 row created.
USER1@mydb>insert into countries values('Zimbabwe');
1 row created.
USER1@mydb>insert into countries values('Zamibia');
1 row created.
USER1@mydb>commit;
Commit complete.
USER1@mydb>select * from countries;
NAME
----------
Zambia
Zimbabwe
Zamibia
4.2對(duì)測(cè)試表進(jìn)行更新
USER1@mydb>update countries set name='Namibia';
3 rows updated.
USER1@mydb>commit;
Commit complete.
USER1@mydb>select * from countries;
NAME
----------
Namibia
Namibia
Namibia
4.3查詢行的所有版本,確定錯(cuò)誤的事務(wù)ID
USER1@mydb>select name,versions_xid,versions_operation from countries versions between scn minvalue and maxvalue ;
NAME VERSIONS_XID V
---------- ---------------- -
Namibia 080007000F040000 U
Namibia 080007000F040000 U
Namibia 080007000F040000 U
Zamibia 040009003C030000 I
Zimbabwe 040009003C030000 I
Zambia 040009003C030000 I
6 rows selected.
4.4查詢FLASHBACK_TARNSACTION_QUERY視圖看到該事務(wù)影響的行,并給出如何取消影響的SQL語句。
--XID列是RAW類型的,VERSIONS_XID偽列是十六進(jìn)制的,需要使用類型強(qiáng)制轉(zhuǎn)換函數(shù)。
SYS@mydb>select operation,undo_sql from flashback_transaction_query where xid=hextoraw('080007000F040000');
OPERATIO UNDO_SQL
-------- ------------------------------------------------------------------------------------------------------------------------
UPDATE update "USER1"."COUNTRIES" set "NAME" = 'Zamibia' where ROWID = 'AAASjKAAEAAAACVAAC';
UPDATE update "USER1"."COUNTRIES" set "NAME" = 'Zimbabwe' where ROWID = 'AAASjKAAEAAAACVAAB';
UPDATE update "USER1"."COUNTRIES" set "NAME" = 'Zambia' where ROWID = 'AAASjKAAEAAAACVAAA';
--還可以使用DBMS_FLASHBACK包進(jìn)行閃回事務(wù)
execute sys.dbms_flashback.transaction_backout(numtxns=>2,xids=>sys.xid_array('080007000F040000'),options=>dbms_flashback.cascade);
5、閃回?cái)?shù)據(jù)歸檔 --保證將表閃回到過去任何時(shí)間。
可以在預(yù)先存在的表空間中創(chuàng)建歸檔,但在新表空間中更加明智。
create flashback archive default hrarch tablespace fbda1 quota 10g retention 5 year;
--default關(guān)鍵字表示除非另行說明將用作所有表的歸檔。
alter flashback archive hrarch set default;
--quota顯示歸檔在表空間中占用的空間??梢栽谠械谋砜臻g或另一個(gè)表空間中添加更多的空間。
alter flashback archive hrarch add tablespace fbda2 quota 10g;
--可以調(diào)整保留時(shí)間
alter flashback archive hrarch modify retention 7 year;
--數(shù)據(jù)超過了指定的保留期限,FBDA進(jìn)程自動(dòng)從歸檔中刪除。在過期之前也可以手動(dòng)進(jìn)行刪除
alter flashback archive hrarch purge before timestamp to_timestamp('01-01-2009','dd-mm-yyyy');
--只有FLASHBACK ARCHIVE ADMINISTER系統(tǒng)權(quán)限能夠創(chuàng)建、修改或刪除歸檔以及控制歸檔的保留和清除。
grant flashback archive administer to fbdaadmin;
--必須授予用戶歸檔的FLASHBACK ARCHIVE權(quán)限以便能夠?qū)Ρ磉M(jìn)行歸檔。
grant flashback archive on hrarch to hr;
--啟用表的歸檔保護(hù)
alter table hr.employees flashback archive hrarch;
--刪除表的歸檔保護(hù)
alter table hr.employees no flashback archive;
--刪除閃回?cái)?shù)據(jù)歸檔
drop flashback archive hrarch;
參考《OCP_OCA認(rèn)證考試指南全冊(cè)__ORACLE_DATABASE_11G》
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