Database Systems The CompleteBook 2nd Edition Suppose that

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Database Systems The CompleteBook (2nd Edition)

Suppose that the relation Star sin discussed in Example 8.14 required 100 pages rather than 10, but all other assumptions of that example continued to hold. Give formulas in terms of p_1 and p_2 to measure the cost of queries Q_1 and Q_0 and insertion I, under the four combinations of index/no index discussed there.

Solution

Action

No Index

Star Index

Movie Index

Both Indexes

Q1

100

4

100

4

Q2

100

100

4

4

I

2

4

4

6

Average

2 + 98p₁ + 98p₂

4+96p₂

4 + 96p₁

6 – 2p₁ – 2p₂

Explanation:

Action	No Index	Star Index	Movie Index	Both Indexes
Q1	100	4	100	4
Q2	100	100	4	4
I	2	4	4	6
Average	2 + 98p1 + 98p2	4+96p2	4 + 96p1	6 – 2p1 – 2p2