ocp 19c考题，科目082考试题(22)- drop columns

22、Choose threeWhich 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 committedC) 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.source:cuug