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## ACS-4902 Assignment 2 due: Feb. 17, 2014

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**i**j h k f g 1 2 3 3 8 8 ACS-4902 Assignment 2 due: Feb. 17, 2014 1.(25) Give the result of the join operation over the following two relations with the join condition A = B. Use the merge join method and describe the computation process. A C B D a b c e f g 3 3 5 6 7 8**PREREQUISITE**SECTION CourseNum=CourseNum CourseNum=CourseNum ACS-4902 Assignment 2 due: Feb. 17, 2014 2.(25) Generate an optimal query tree for the following query (see Fig. 1.2 for relation schemas): Name, StuNumber((Dept=‘BC’(COURSE) GRADE_REPORT) STUDENT) SEcIdentifier=SecIdentifier StuNumber=StuNumber**ACS-4902 Assignment 2**due: Feb. 17, 2014 3.(25) Assume that X = 90, Y = 100, N = 12, M = 8. Show the the results by executing the following interleaved transactions. Are the results correct? Explain your results. TimeTransaction1Transaction2 1 READ(X) 2 X:=X-N 3 READ(X) 4 X:=X+M 5 WRITE(X) 6 READ(Y) 7 WRITE(X) 8 Y:=Y+N 9 WRITE(Y)**ACS-4902 Assignment 2**due: Feb. 17, 2014 4.(25) Given the following schedules. Show which is recoverable, cascadeless or strict. Explain why. i) R1(X), R2(X), R1(Y), R2(Z), W1(X), R1(Z), W2(Z), C2, W1(Y), C1. ii) R1(X), W1(X), R2(Z), R2(Y), R2(X), W2(Y), C2, A1. iii) R1(X), W1(X), R1(Y), R2(Y), W2(Y), W1(Y), C1, R2(X), W2(X), C2.