这一项功能使得rman的恢复目录更加安全。基本原理是：

catalog

owner创建一个传统的恢复目录，并grantrecover_catalog_owner权限给虚拟专用catalog用户，虚拟专用catalog用户还需要被授予注册数据库权限。之后使用该虚拟专用catalog用户去注册特定的数据库。该虚拟专用catalog用户只能访问他自己注册的数据库，而原catalogowner可以看到所有虚拟专用catalog用户注册的数据库。

我打个比方：一分多，的意思。

[oracle@station90~]$.oraenv

ORACLE_SID=[orcl]?rcat

TheOraclebaseforORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1is/u01/app/oracle

[oracle@station90~]$sqlplus/nolog

SQL*Plus:Release11.2.0.1.0ProductiononWedOct2311:24:042013

Copyright(c)1982,2009,Oracle.Allrightsreserved.

SQL>conn/assysdba

Connected.

SQL>createuserv90identifiedbyoracle_4Udefaulttablespacercatquotaunlimitedonrcat;

SQL>grantrecovery_catalog_ownertov90;

Grantsucceeded.

[oracle@station90~]$.oraenv

ORACLE_SID=[rcat]?orcl

TheOraclebaseforORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1is/u01/app/oracle

[oracle@station90~]$rmantarget/catalogu90/oracle_4U@rcat

RecoveryManager:Release11.2.0.1.0-ProductiononWedOct2311:28:232013

Copyright(c)1982,2009,Oracleand/oritsaffiliates.Allrightsreserved.

connectedtotargetdatabase:ORCL(DBID=1343950367)

connectedtorecoverycatalogdatabase

RMAN>grantregisterdatabasetov90;

Grantsucceeded.

RMAN>

[oracle@station90~]$rmantarget/catalogv90/oracle_4U@rcat

RecoveryManager:Release11.2.0.1.0-ProductiononWedOct2314:57:402013

Copyright(c)1982,2009,Oracleand/oritsaffiliates.Allrightsreserved.

connectedtotargetdatabase:ORCL(DBID=1343950367)

connectedtorecoverycatalogdatabase

RMAN>createvirtualcatalog;

foundeligiblebasecatalogownedbyU90

createdvirtualcatalogagainstbasecatalogownedbyU90

注意最后两句很能说明：“一分多”的原理。

rmantarget/catalogv90/oracle_4U@rcat

RecoveryManager:Release11.2.0.1.0-ProductiononWedOct2315:00:332013

Copyright(c)1982,2009,Oracleand/oritsaffiliates.Allrightsreserved.

connectedtotargetdatabase:ORCL(DBID=1343950367)

connectedtorecoverycatalogdatabase

RMAN>registerdatabase;

databaseregisteredinrecoverycatalog

startingfullresyncofrecoverycatalog

fullresynccomplete

以下直接连入catalog查询，就是最好的关于“一分多”的说明：

SQL*Plus:Release11.2.0.1.0ProductiononWedOct2315:36:522013

Copyright(c)1982,2009,Oracle.Allrightsreserved.

SQL>connu90/oracle_4U@rcat

Connected.

SQL>select*fromdb;

DB_KEYDB_IDCURR_DBINC_KEY

----------------------------------

142913515900151430

169113518503221692

338013570656993381

220313460414802204

321013509509033211

239413531462362395

388213439503673883

7rowsselected.

SQL>connv90/oracle_4U@rcat

Connected.

SQL>select*fromdb;

DB_KEYDB_IDCURR_DBINC_KEY

----------------------------------

388213439503673883

SQL>