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.
source:cuug
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