Consider relation Executives(ename, title, dname, address), where all attributes have
the same length and ename is a candidate key. The relation contains 12; 000 pages and the
buffer has 10 pages. Assume that 10% tuples satisfy the following query.
Select E.title, Count(*)
From Executives E
Where E.dname > ’W%’
Group by E.title
For each of the following scenarios, describe the most efficient evaluation plan for the query
and estimate its cost in pages.
(a) Only a clustering B+ tree index on title is available.
(b) Only an unclustered B+ tree index on title is available.
(c) Only a clustered B+ tree index on dname is available.
(d) Only a clustering B+ tree index on (dname, title) is available.
(e) Only a clustering B+ tree index on (title, dname) is available.
This question belongs to computer science and discusses about most efficient evaluation plan for a query.
Word count: NA
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