Consider a disk with average seek time of 10 ms, average rotational latency of 5 ms, anda transfer time of 1 ms for a 4KB block. The cost of reading/writing a block is the sum ofthese values (i.e. 16 ms). We are asked to sort a large relation consisting of 10,000,000blocks of 4KB each. For this, we use a computer on which the main memory available forbuffering is 320 blocks (a bit small memory). We begin as usual by creating sorted runsof 320 blocks each in phase 1. Then, we do 319-way merges. Determine the number ofphases needed, and evaluate the cost of the Multi Phase Multiway Merge Sort.
Ex. 7. (4 pts)
For each of the following relation schemas and sets of FD's:
a) R(A,B,C,D) with FD's AB C, B D, CD A, AD B.
b) R(A,B,C,D) with FD's A B, B C, C D, D A.
Indicate all the BCNF violations. Decompose the relations, as necessary, into collections
of relations that are in BCNF.