Oracle Database SQL — Question 37

Which three are true about dropping columns from a table? (Choose three.)

Answer options

• A. A column must be set as unused before it is dropped from a table.
• B. A primary key column cannot be dropped.
• C. Multiple columns can be dropped simultaneously using the ALTER TABLE command.
• D. A column can be removed only if it contains no data.
• E. A column that is referenced by another column in any other table cannot be dropped.
• F. A column drop is implicitly committed.

Correct answer: C, F

Explanation

The correct answers are C and F because multiple columns can indeed be removed simultaneously with the ALTER TABLE command, and dropping a column is automatically committed. Option A is incorrect as a column does not need to be set as unused to be dropped, B is wrong because primary key columns can be dropped under certain conditions, D is false since a column can contain data and still be dropped, and E is misleading as there are ways to drop referenced columns with constraints.