7、 检查数据库的数据（完全恢复）
SQL select * from test;
A
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说明：
1、采用热备份，需要运行在归档模式下，可以实现数据库的完全恢复，也就是说，从备份后到数据库崩溃时的数据都不会丢失;
2、可以采用全备份数据库的方式备份，对于特殊情况，也可以只备份特定的数据文件，如只备份用户表空间（一般情况下对于某些写特别频繁的数据文件，可以单独加大备份频率）；
3、如果在恢复过程中，发现损坏的是多个数据文件，即可以采用一个一个数据文件的恢复方法（第5步中需要对数据文件一一脱机，第6步中需要对数据文件分别恢复），也可以采用整个数据库的恢复方法；
4、如果是系统表空间的损坏，不能采用此方法。
4.2.2 RMAN备份方案
RMAN也可以进行联机备份，而且备份与恢复方法将比OS备份更简单可靠。
1、连接数据库，创建测试表并插入记录
SQL connect internal/password as sysdba;
Connected.
SQL create table test(a int) tablespace users;
Table created
SQL insert into test values(1);
1 row inserted
SQL commit;
Commit complete
2、 备份数据库表空间users
C:\rman
Recovery Manager: Release 8.1.6.0.0 - Production
RMAN connect rcvcat rman/rman@back
RMAN-06008: connected to recovery catalog database
RMAN connect target internal/virpure
RMAN-06005: connected to target database: TEST (DBID=1788174720)
RMAN run{
2 allocate channel c1 type disk;
3 backup tag 'tsuser' format 'd:\backup\tsuser_%u_%s_%p'
4 tablespace users;
5 release channel c1;
6 }
RMAN-03022: compiling command: allocate
RMAN-03023: executing command: allocate
RMAN-08030: allocated channel: c1
RMAN-08500: channel c1: sid=16 devtype=DISK
RMAN-03022: compiling command: backup
RMAN-03025: performing implicit partial resync of recovery catalog
RMAN-03023: executing command: partial resync
RMAN-08003: starting partial resync of recovery catalog
RMAN-08005: partial resync complete
RMAN-03023: executing command: backup
RMAN-08008: channel c1: starting full datafile backupset
RMAN-08502: set_count=5 set_stamp=494177612 creation_time=16-MAY-03
RMAN-08010: channel c1: specifying datafile(s) in backupset
RMAN-08522: input datafile fno=00003 name=D:\Oracle\ORADATA\TEST\USER01.DBF
RMAN-08013: channel c1: piece 1 created
RMAN-08503: piece handle=D:\BACKUP\TSUSER_05EN93AC_5_1 comment=NONE
RMAN-08525: backup set complete, elapsed time: 00:00:01
RMAN-03023: executing command: partial resync
RMAN-08003: starting partial resync of recovery catalog
RMAN-08005: partial resync complete
RMAN-03022: compiling command: release
RMAN-03023: executing command: release
RMAN-08031: released channel: c1
RMAN
3、 继续在测试表中插入记录
SQL insert into test values(2);
1 row inserted
SQL commit;
Commit complete
SQL select * from test;
A
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SQL alter system switch logfile;
System altered.
SQLr
1* alter system switch logfile;
System altered.
4、 关闭数据库，模拟丢失数据文件
SQL shutdown immediate;
Database closed.
Database dismounted.
Oracle instance shut down
C:\del D:\Oracle\ORADATA\TEST\USER01.DBF
5、 启动数据库，检查错误
SQL startup
Oracle instance started.
Total System Global Area
102020364 bytes
Fixed Size
70924 bytes
Variable Size
85487616 bytes
Database Buffers
16384000 bytes
Redo Buffers
77824 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 3 - see DBWR trace file
ORA-01110: data file 3: 'D:\Oracle\ORADATA\TEST\USER01.DBF'
6、 先打开数据库
SQL alter database datafile 3 offline drop;
Database altered.
SQL alter database open;
Database altered.
7、 恢复该表空间
恢复脚本可以是恢复单个数据文件
run{
allocate channel c1 type disk;
restore datafile 3;
recover datafile 3;
sql 'alter database datafile 3 online';
release channel c1;
}
也可以是,恢复表空间
run{
allocate channel c1 type disk;
restore tablespace users;
recover tablespace users;
sql 'alter database datafile 3 online';
release channel c1;
}
过程如下：
C:\rman
Recovery Manager: Release 8.1.6.0.0 - Production
RMAN connect rcvcat rman/rman@back
RMAN-06008: connected to recovery catalog database
RMAN connect target internal/virpure
RMAN-06005: connected to target database: TEST (DBID=1788174720)
RMAN run{
2 allocate channel c1 type disk;
3 restore datafile 3;
4 recover datafile 3;
5 sql 'alter database datafile 3 online';
6 release channel c1;
7 }
//输出内容冗长，省略--编者
RMAN
8、 检查数据是否完整
SQL alter database open;
Database altered.
SQL select * from test;
A
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说明：
1、RMAN也可以实现单个表空间或数据文件的恢复，恢复过程可以在mount下或open方式下，如果在open方式下恢复，可以减少down机时间;
2、如果损坏的是一个数据文件，建议offline并在open方式下恢复;
3、这里可以看到，RMAN进行数据文件与表空间恢复的时候，代码都比较简单，而且能保证备份与恢复的可靠性，所以建议采用RMAN的备份与恢复.
4.3丢失多个数据文件，实现整个数据库的恢复.
4.3.1 OS备份方案
OS备份归档模式下损坏（丢失）多个数据文件，进行整个数据库的恢复
1、 连接数据库，创建测试表并插入记录
SQL connect internal/password as sysdba;
Connected.
SQL create table test(a int);
Table created
SQL insert into test values(1);
1 row inserted
SQL commit;
Commit complete
2、 备份数据库，备份除临时数据文件后的所数据文件
SQL @hotbak.sql 或在DOS下 svrmgrl @hotbak.sql
3、 继续在测试表中插入记录
SQL insert into test values(2);
1 row inserted
SQL commit;
Commit complete
SQL select * from test;
A
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SQL alter system switch logfile;
System altered.
SQL alter system switch logfile;
System altered.
4、 关闭数据库，模拟丢失数据文件
