Question 10824 – APPSC-2016-DL-CS
November 26, 2023Logical-Reasoning
November 26, 2023Database-Management-System
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Question 24
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Consider the following relations P(X,Y,Z), Q(X,Y,T) and R(Y,V).
How many tuples will be returned by the following relational algebra query?
∏x(P.Y=R.Y ∧ R.V=V2)(P × R)) – ∏x(Q.Y=R.Y ∧ Q.T>2)(Q × R))
How many tuples will be returned by the following relational algebra query?
∏x(P.Y=R.Y ∧ R.V=V2)(P × R)) – ∏x(Q.Y=R.Y ∧ Q.T>2)(Q × R))
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0
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1
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2
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3
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Question 24 Explanation:
σ(P.Y = R.Y ∧ R.V = V2)(P × R)
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R))
σ(Q.Y = R.Y ∧ Q.T>2)(Q × R)
∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R)) – ∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R))
σ(Q.Y = R.Y ∧ Q.T>2)(Q × R)
∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R)) – ∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
Correct Answer: B
Question 24 Explanation:
σ(P.Y = R.Y ∧ R.V = V2)(P × R)
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R))
σ(Q.Y = R.Y ∧ Q.T>2)(Q × R)
∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R)) – ∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R))
σ(Q.Y = R.Y ∧ Q.T>2)(Q × R)
∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))
∏x(σ(P.Y = R.Y ∧ R.V = V2)(P × R)) – ∏x(σ(Q.Y = R.Y ∧ Q.T>2)(Q × R))