Exercise 14.2 Consider a relation R(a,b,c,d,e) containing 5,000,000 records, where each da...

Exercise 14.2 Consider a relation R(a,b,c,d,e) containing 5,000,000 records, where each data page of the relation holds 10 records. R is organized as a sorted file with secondary indexes. Assume that R.a is a candidate key for R, with values lying in the range 0 to 4,999,999, and that R is stored in R.a order. For each of the following relational algebra queries, state which of the following approaches (or combination thereof) is most likely to be the cheapest:

• Access the sorted file for R directly.
• Use a clustered B+ tree index on attribute R.a.
• Use a linear hashed index on attribute R.a.
• Use a clustered B+ tree index on attributes (R.a,R.b).
• Use a linear hashed index on attributes (R.a,R.b).
• Use an unclustered B+ tree index on attribute R.b.

1. σ_{a<50,000∧b<50,000}(R)
2. σ_{a=50,000∧b<50,000}(R)
3. σ_{a>50,000∧b=50,000}(R)
4. σ_{a=50,000∧a=50,010} (R)
5. σ_{a≠50,000∧b=50,000}(R)
6. σ_{a<50,000∨b=50,000}(R)