(a) Consider the following relations: Employee (e-id, e-name, address, phone), s

Question

(a) Consider the following relations:

Employee(e-id, e-name, address, phone), sorted on e-id

Manager(e-id, e-name, department), sorted on e-id
How many block transfers is required for the merge phase of the sort-merge algorithm to implement Employee Manager? Assume that the sizes of relations Employeeand Manager are M and N blocks, respectively.

(b) Consider the following relations:

Student(s-id, s-name, gender), sorted on gender with domain (Male, Female)

Instructor(i-id, i-name, gender), sorted on gender with domain (Male, Female) How many block transfers is required for the merge phase of the sort-merge algorithm to implement Student Instructor? Assume that the sizes of relations Student andInstructor are M and N blocks, respectively

Explanation / Answer

a)Let block size of employee be, bm
block size of Manager, bn

bmn is the writing result of join

number of blocks for merge join =(bm+bn+bnm)

->this is already sorted on id.

b)this is sorted on gender, so sort on id has to be done.

Student block size= bm;
Instructor block size =bn;

each block is read once,

number of blocks for merge join =bm+bn+sorting cost +bmn

/for any clarification, pleae do comments

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