现象：
在做表空间恢复演练时，遇到如下错误提示：
SQL> alter database datafile 4 online;
alter database datafile 4 online
*
ERROR at line 1:
ORA-01122: database file 4 failed verification check
ORA-01110: data file 4: ‘/ora/app/oracle/oradata/orcl/users01.dbf‘
ORA-01210: data file header is media corrupt
解决方法：
分析原因：
[[email protected] hotback]$ oerr ora 1122
01122, 00000, "database file %s failed verification check"
// *Cause: The information in this file is inconsistent with information
// from the control file. See accompanying message for reason.
// *Action: Make certain that the db files and control files are the correct
// files for this database.
[[email protected] hotback]$ oerr ora 1110
01110, 00000, "data file %s: ‘%s‘"
// *Cause: Reporting file name for details of another error. The reported
// name can be of the old file if a data file move operation is
// in progress.
// *Action: See associated error message.
[[email protected] hotback]$ oerr ora 1210
01210, 00000, "data file header is media corrupt"
// *Cause: The file header block is internally inconsistent. The beginning
// of the block has a header with a checksum and other data for
// insuring the consistancy of the block. It is possible that
// the last disk write did not operate correctly. The most likely
// problem is that this is not a datafile for any database.
// *Action: Have operating system make correct file available to database.
// If the trace file dump indicates that only the checksum is wrong,
// restore from a backup and do media recovery.
基本可知，还原的数据文件是不正确的。认真检查后，果然是：
ho cp ‘/ora/app/oracle/backup/hotback/con01.ctl‘ ‘/ora/app/oracle/oradata/orcl/users01.dbf‘
把备份的控制文件当数据文件给还原回去了！
重新还原：
SQL> ho cp ‘/ora/app/oracle/backup/hotback/users01.dbf‘ ‘/ora/app/oracle/oradata/orcl/users01.dbf‘
后续步骤正确执行。