多项选择题 Which is the correct way to connect to both the target database and the recovery catalog from the RMAN command line？（） Assume that the target database is called ORCL and that the recovery catalog database is called RCAT. Also assume that the recovery-catalog owner is called RCAT_OWN. Assume the environment is configured for the ORCL database.

单项选择题 How can you reverse the effects of an ALTER DISKGROUP ... DROP DISK command if it has alreadycompleted?（）

单项选择题 How can you reverse the effects of an ALTER DISKGROUP ... DROP DISK command if it has not yetcompleted?（）