DBMS Grand Test 1 Question17

+1 vote

Consider the following schema 

Student (Sid ,Sname)

Teacher ( Tid, Tname)

Likes(Sid, Tid)

\dpi{120} \bg_white \left \{ t|\exists S \in Student \forall B\in Teacher \exists L \in Likes (S.Sid=L.Sid\wedge B.Tid =L.Tid \wedge t.name=S.sname)\right \}

What is the output of above tuple relational calculus query

(A) It prints names of the students who likes every teacher

(B) It prints names of the students if they like some teacher

(C) It prints names of the students who do not like some teacher 

(D) It prints empty set

asked Sep 10, 2016 in DBMS by getgatebook (36,850 points)
reshown Dec 28, 2018 by getgatebook

1 Answer

+1 vote
it tuple relational caluculas so that its clealy see that domain is some student  and every teacher...so finally it prints names of the students who like every teacher option A is correct
answered Sep 19, 2016 by (1,100 points)
Answer:
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