GATE 2010 CS (CS1) – Question 53

Databases · Relational Model: Relational Algebra, Tuple Calculus, SQL · 2 marks · Multiple choice

Relations R(A,B,C) and S(B,D,E) satisfy B→A and A→C. R has 200 tuples and S has 100. What is the maximum tuple count in R natural-join S?

100
200
300
2000

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (A) 100

Explanation

In R, B determines A and transitively C, so B is a key. Each S tuple can therefore match at most one R tuple on B. There are one hundred S tuples, giving an upper bound of one hundred, attainable when each has a matching B. Thus A.

More Relational Model: Relational Algebra, Tuple Calculus, SQL questions

GATE 2015 CS (CS2) Q40 – R1(A,B)=(1,5),(3,7) and R2(A,C)=(1,7),(4,9). Let R be their full natural outer join.…
GATE 2015 CS (CS3) Q29 – Cinema(theater,address,capacity) stores theaters. Complete the query to always return…
GATE 2021 CS (CS2) Q41 – emp(empId,name,gender,salary,deptId) has key empId, and each employee belongs to one…
GATE 2026 CS (CS1) Q30 – Let P, Q, R and S be the attributes of a relation in a relational schema. Let X Y indicate…
GATE 2026 CS (CS1) Q43 – Consider a relational database schema with two relations R(P, Q) and S(X, Y). Let E = \ u…
GATE 2025 CS (CS1) Q39 – Consider two relations describing teams and players in a sports league: - teams(tid,…

All Relational Model: Relational Algebra, Tuple Calculus, SQL questions →