281.You are working on a 24X7 database. You want to design a backup strategy for your database that
uses user managed backups. You want to be able to perform all backups while the database remains
online.
Which statement about performing user-managed backups in a 24x7 environment is true?
A. You must have change tracking enabled in your database
B. Your database must be running in NOARCHIVELOG mode
C. To back up a tablespace, it must be in backup mode
D. To back up a tablespace, it must first be taken offline
Answer: C
答案解析：
S手工热备份脚本参考：http://blog.csdn.net/rlhua/article/details/11850629
手工热备份，先将数据库或表空间置为备份模式，然后开始OS拷贝，最后结束备份模式。
这个数据库为24*7，则可以将各个表空间置为备份模式开始备份。