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2 votes
2 votes

Q.Consider the following query :

Select E.no,COUNT(*)

FROM Employee E

GROUP BY E.no

If an index on eno is available,the query can be answered by scanning only the index if

A) the index is only hash and clustered

B) the index is only B+ tree and clustered

C)index can be hash or B+ tree and clustered or non-clustered

D)index can be hash or B+ tree and clustered

1 Answer

2 votes
2 votes

Option (C) is correct index can be hash or B+ tree and clustered or non-clustered

clustered index=(indexing on non-key field, ordered file)..............every other index are non-clustered ............since no information about search key( 'eno' ) i.e whether it is sorted or not ......and also we don't have any information about data file(sorted or not-sorted) so ..........non-clustered index and clustered index both are possible ....option C is correct

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