单项选择题
Which view should a user query to display the columns associated with the constraints on a table owned by the user? （）
A. USER_CONSTRAINTS B. USER_OBJECTS C. ALL_CONSTRAINTS D. USER_CONS_COLUMNS E. USER_COLUMNS
单项选择题 The user Alice wants to grant all users query privileges on her DEPT table. Which SQL statement accomplishes this? （）
单项选择题 Which constraint can be defined only at the column level? （）
多项选择题 In which two cases would you use an outer join? （）
