assignment-378

Consider following relations”

Question 1: If the relations are fragmented into R1 and R2 then comment on the completeness and disjointness of the relations

• R1 = σ RESP = “Manager” OR RESP = “Engineer”(ASG)
• R1 = σ TITLE < “Programmer”(EMP)
• R1 = σ Salary < 30000 (PAY)

R2= σ RESP < “Engineer” (R)

R2= σ TITLE <= “Syst_Anal.”(EMP)

R2= σ Salary ≥ 30000 (PAY)

Question 2:

Assume P1: SAL < 27000 and P2: Sal >= 27000 are two simple predicates. Fragment PAY relation based on P1 and P2. Using these fragments perform fragmentation of EMP and show completeness, disjointness and reconstruction on fragmentation of emP.

Question 3:

Consider the following query based on above relations:

Select ENAME, PNAME

From EMP E, ASG A, PROJ P

Where E.ENO = A.ENO

And A.PNO = P.PNO

And (TITLE = “Elec. Eng” OR A.PNO < “P3”)

1. Write relational Algebra expression fot the query
2. Draw the canonical tree
3. Obtain optimized tree

Question 4:

Simplify the following query:

Select ENO from ASG

Where RESP = ‘Analyst’

and NOT (PNO =”P2” or DUR = 12)

and NOT PNO =”P2”

or DUR = 12

Question 5:

In above relations if PFOJ is horizontally fragmented using the queries:

PROJ1: Select * from PROJ where PNO <= ’P3’

PROJ2: Select * from PROJ where PNO > ’P3’

Transform the following query into a reduced query on fragments:

Select BUGET from PROJ, ASG

Where PROJ.PNO = ASG.PNO

And PNO = “P4”

 

Do you need a similar assignment done for you from scratch? We have qualified writers to help you. We assure you an A+ quality paper that is free from plagiarism. Order now for an Amazing Discount!
Use Discount Code "Newclient" for a 15% Discount!

NB: We do not resell papers. Upon ordering, we do an original paper exclusively for you.