1 alter database：修改数据文件
alter database datafile 4 offline;
alter database datafile '/opt/oracle/datafile/users01.dbf' resize 100M;
alter database datafile '/opt/oracle/datafile/users01.dbf' autoextend on next 100M maxsize 1000M;
alter database datafile 4 end backup;
2 alter database：修改临时文件（tempfile）
alter database tempfile 4 resize 100M;
alter database tempfile 4 autoextend on next 100M maxsize 1000M;
alter database tempfile 4 drop including datafiles;
alter database tempfile 4 offline;
3 alter database：归档日志（archivelog）模式命令
alter database archivelog;
alter database noarchivelog;
alter database force logging;
alter database clear logfile '/opt/oracle/logfiles/redo01.rdo';
alter database clear unarchived logfile '/opt/oracle/logfiles/redo01.rdo';
alter database add supplemental log data;
alter database add supplemental log data (primary key,unique);
alter database drop supplemental log data;
4 alter database：控制文件操作
alter database backup controlfile to trace;
alter database backup controlfile to trace as '/opt/oracle/logfile_backup/backup_logfile.trc' reuse resetlogs;
alter database backup controlfile to '/opt/oracle/logfile_backup/backup_logfile.ctl';
5 alter database：创建数据文件
alter database create datafile '/opt/oracle/datafile/users01.dbf' as '/opt/oracle/datafile/users01.dbf';
alter database create datafile 4 as '/opt/oracle/datafile/users01.dbf';
alter database create datafile '/opt/oracle/datafile/users01.dbf' as new;
6 alter database：日志文件命令
alter database add logfile group 2 ('/opt/oracle/logfiles/redo02a.rdo','/opt/oracle/logfile/redo02b.rdo') size 300M reuse;
alter database add logfile member '/opt/oracle/logfiles/redo02c.rdo' to gourp 2
alter database add logfile thread 3 group 2 ('/opt/oracle/logfiles/redo02a.rdo','/opt/oracle/logfiles/redo02b.rdo') size 300M reuse;
alter database drop logfile group 3
alter database drop logfile member '/opt/oracle/logfiles/redo02b.rdo';
7 alter database：安装和打开数据库
alter database mount;
alter database open;
8 alter database：移动或重命名数据库文件或联机重做日志
注意：数据库必须已经安装才能重命名或移动联机重做日志。数据库必须已经安装或数据文件处于脱机状态时，才能移动数据库中的数据文件。
alter database rename file '/ora/datafile/oldfile.dbf' to '/ora/datafile/newfile.dbf';
9 alter database：以只读方式打开数据库
alter database open read only;
10 alter database：使用resetlogs打开数据
alter database open resetlogs;
11 alter database：恢复数据库
对数据库的恢复，建议使用recover命令代替。