Exercise 12.5 Consider again the schema with the Sailors relation: Sailors(sid: integer,...

Exercise 12.5 Consider again the schema with the Sailors relation:

  Sailors(sid: integer, sname: string, rating: integer, age: real)

Assume that each tuple of Sailors is 50 bytes long, that a page can hold 80 Sailors tuples, and that we have 500 pages of such tuples. For each of the following selection conditions, estimate the number of pages retrieved, given the catalog information in the question.

1. Assume that we have a B+-tree index T on the search key 〈 Sailors.sid 〉, and assume that IHeight(T) = 4, INPages(T) = 50, Low(T) = 1, and High(T) = 100,0(
   1. σ_{Sailors.sid<50,000}(Sailors)
   2. σ_{Sailors.sid=50,000}(Sailors)
2. Assume that we have a hash index T on the search key 〈 Sailors.sid 〉, and assumethat IHeight(T) = 2, INPages(T) = 50, Low(T) = 1, and High(T) = 100,000.
   1. σ_{Sailors.sid<50,000}(Sailors)
   2. σ_{Sailors.sid=50,000}(Sailors)