Oracle no backup restores various scenarios

1. Recover password file
Orapwd file= $ORACLE _HOME/DBS/ORAPWOCP password=oracle force=y ignorecase=y;

--Note: whether the common user's password is case-sensitive and Sec_case_sensitive_logon by the initial parameter, and not the password file processing

2. Recovery parameter file

Find Alert_sid.log Log

3. No backup control files
Scenario 1: Reconstruction of online logs without compromising
RM-RF control*
Shutdown abort;
Startup Nomount;
CREATE controlfile Reuse DATABASE "Bxdb" Noresetlogs ...
Reocver database;
ALTER DATABASE open;
ALTER tablespace TEMP ADD tempfile '/u01/app/oracle/oradata/bxdb/temp01.dbf ' reuse;
Scenario 2: Rebuilding in case of online log corruption
Shutdown immediate; -Note that the database should be shut down properly, otherwise the system will be required to do the recovery???
RM-RF control*
RM-RF redo*
Startup Nomount;
CREATE controlfile Reuse DATABASE "Bxdb" Resetlogs ...
Recover database until cancel using BACKUP controlfile;--rman>recover database until sequence 2;
ALTER DATABASE open resetlogs;
ALTER tablespace TEMP ADD tempfile '/u01/app/oracle/oradata/bxdb/temp01.dbf ' reuse;
Scenario 3: Rebuilding with read-only data files
Startup Nomount;
CREATE controlfile Reuse DATABASE "Bxdb" Noresetlogs ...
Recover database; --recover database using Backup controlfile;
ALTER DATABASE open; --alter database open resetlogs;
Alter DATABASE rename file '/u01/app/oracle/product/11g/dbs/missing00005 ' to '/u01/app/oracle/oradata/bxdb/tp2.dbf ';
Alter Tablespace TP12 Online; --Cannot set up data file online (ALTER DATABASE datafile 7;)
ALTER tablespace TEMP ADD tempfile '/u01/app/oracle/oradata/ocp/temp01.dbf ' reuse;
Scenario 4: Using Control file Snapshot recovery
Cp/u01/app/oracle/product/11g/dbs/snapcf_ocp.f/u01/app/oracle/oradata/ocp/control01.ctl
Cp/u01/app/oracle/product/11g/dbs/snapcf_ocp.f/u01/app/oracle/oradata/ocp/control02.ctl
Cp/u01/app/oracle/product/11g/dbs/snapcf_ocp.f/u01/app/oracle/oradata/ocp/control03.ctl
startup Mount;
Recover database using Backup controlfile; --rman>recover database;

ALTER DATABASE open resetlogs;

4. Recover Data files
RM-RF tp5.dbf;
ALTER DATABASE datafile 8 offline;
ALTER DATABASE create datafile '/u01/app/oracle/oradata/ocp/tp12.dbf ';
SELECT * from T20; No file found---error
Recover DataFile 8;

ALTER DATABASE datafile 8 online;

5. Restoration of temporary documents
Alter TABLESAPCE temp add tempfile '/u01/app/oracle/oradata/oca/temp02.dbf ' size 20M autoextend on;

Alter TABLESAPCE temp drop tempfile '/u01/app/oracle/oradata/oca/temp01.dbf ';

6. Redo Online Redo Log
Scenario 1: Each log group has two online log members, and group 1th is one of the redo01B.log damaged
ALTER DATABASE drop logfile member '/u01/app/oracle/oradata/oca/redo01b.log ';
ALTER DATABASE add logfile member '/u01/app/oracle/oradata/oca/redo01b.log ' to group 1;
Scenario 2: Each log group has two online log members, and all logs in Group 1th (Redo01A.log and Redo01B.log) are corrupted
ALTER DATABASE clear logfile Group 1;
ALTER DATABASE Clear unarchived logfile Group 1;
Scenario 3: All log groups are corrupted
RM-RF redo*
Shutdown immediate;
startup Mount;
Recover database until cancel;

ALTER DATABASE open resetlogs;

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