Q67 Which three statements are true about dropping and unused columns in an Oracle database? (Choose three.)
- (A). A primary key column referenced by another column as a foreign key can be dropped if using the CASCADE option.
- (B). An UNUSED column’s space is reclaimed automatically when the block containing that column is next queried.
- (C). An UNUSED column’s space is reclaimed automatically when the row containing that column is next queried.
- (D). Partition key columns cannot be dropped.
- (E). A DROP COLUMN command can be rolled back
- (F). A column that is set to UNUSED still counts towards the limit of 1000 columns per table
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