关于RMAN恢复中的switch database …

After the RESTORE command but before the RECOVER command in your RUN 
block, use a SWITCH command to update the control file with the new 
filenames of the datafiles. The SWITCH command is equivalent to the 
SQL statement ALTER DATABASE RENAME FILE. SWITCH DATAFILE ALL updates
 the control file to reflect the new names for all datafiles for 
 which a SET NEWNAME has been issued in the RUN block.


RUN
{
  SQL 'ALTER TABLESPACE users OFFLINE IMMEDIATE';
  SQL 'ALTER TABLESPACE tools OFFLINE IMMEDIATE';
  # specify the new location for each datafile
  SET NEWNAME FOR DATAFILE '/olddisk/users01.dbf' TO 
  '/newdisk/users01.dbf';
  SET NEWNAME FOR DATAFILE '/olddisk/tools01.dbf' TO 
  '/newdisk/tools01.dbf';
  # to restore to an ASM disk group named dgroup, use: 
  # SET NEWNAME FOR DATAFILE '/olddisk/trgt/tools01.dbf'
  # TO '+dgroup';
  RESTORE TABLESPACE users, tools;
  SWITCH DATAFILE ALL; # update control file with new filenames
  RECOVER TABLESPACE users, tools;
}