---

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

---

出自：Oracle认证

显示答案