多项选择题
Which three features are provided by Oracle Net Services？ （）
A.Data encryption. B.User authentication. C.Transparent data conversion D.Configuration and administration mechanisms. E.Support for multiple network transport protocols.
单项选择题 Whenyouareperformingmediarecover，andanarchivedlogislostorcorrupt，whichtypeofrecovermustyouperform？（）
多项选择题 Whichtworolesorprivilegesmustyouhavetoexporttablesownedbyanotheruser？（）
多项选择题 Inwhichthreecasesdoesacheckpointoccur？（）
