You are managing a 24*7 database. The backup strategy for the database is to perform user-managed backups.
Identify two prerequisites to perform the backups. (Choose two.)
A. The database must be opened in restricted mode.
B. The database must be configured to run in ARCHIVELOG mode.
C. The tablespaces are required to be in backup mode before taking the backup.
D. The tablespaces are required to be in read-only mode before taking the backup
7*24 小时的数据库，不能进行冷备份（关闭数据库），所以要开启归档，并且数据库要在打开状态。 B 对，A 错
使用手动备份的时候，如果表空间是在线的，需要将表空间置为备份模式：
ALTER TABLESPACE ... BEGIN BACKUP
备份完成后，再取消备份模式：
ALTER TABLESPACE ... END BACKUP 或者 ALTER DATABASE END BACKUP
C 对
热备份对表空间无影响，在的表空间可以在只读或者读写下进行备份，不用改为只读模式，D 错