Oracle OCP 19c 认证1Z0-082考试题库(第22题)-CUUG内部学员版082题库解析
22、Choose three
Which three are true about dropping columns from a table?
A) A column can be removed only if it contains no data.
B) A column drop is implidtly committed
C) A column that is referenced by another column in any other table cannot be dropped.
D) A column must be set as unused before it is dropped from a table.
E A primary key column cannot be dropped.
F) Multiple columns can be dropped simultaneously using the ALTER TABLE command.