1
GATE CSE 2008
MCQ (Single Correct Answer)
+1
-0.3

Which of the following tuple relational calculus expression(s) is/are equivalent to $$\forall t \in r \left(P\left(t\right)\right)$$?

I. $$\neg \exists t \in r \left(P\left(t\right)\right)$$
II. $$\exists t \notin r \left(P\left(t\right)\right)$$
III. $$\neg \exists t \in r \left(\neg P\left(t\right)\right)$$
IV. $$\exists t \notin r \left(\neg P\left(t\right)\right)$$
A
I only
B
II only
C
III only
D
III and IV only
2
GATE CSE 2006
MCQ (Single Correct Answer)
+1
-0.3
Consider the relations r1(P, Q, R) and r2(R, S, T) with primary keys P and R respectively. The relation r1 contains 2000 tuples and r2 contains 2500 tuples. The maximum size of the join $${r_1} \Join {r_2}$$ is
A
2000
B
2500
C
4500
D
5000
3
GATE CSE 2006
MCQ (Single Correct Answer)
+1
-0.3
Which of the following relational query languages have the same expressive power?

I) Relational algebra
II) Tuple relational calculus restricted to safe expressions
III) Domain relational calculus restricted to safe expressions

A
II and III only
B
I and II only
C
I and III only
D
I, II and III
4
GATE CSE 2005
MCQ (Single Correct Answer)
+1
-0.3

Let r be a relation instance with schema R = (A, B, C, D).

We define $${r_1} = {\pi _{A,B,C}}\left( r \right)$$ and $${r_1} = {\pi _{A,D}}\left( r \right)$$. Let $$s = {r_1}*{r_2}$$ where * denotes natural join. Given that the decomposition of r into r1 and r2 is lossy, which one of the following is TRUE?
A
$$s \subset r$$
B
$$r \cup s =r$$
C
$$r \subset s$$
D
$$r * s = s$$
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Graduate Aptitude Test in Engineering
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CBSE
Class 12