Skip to content
GATEiit

GATE CSE 2026 Session 1 Q43: Relational algebra equivalent of a tuple calculus join query

Question

Consider a relational database schema with two relations R(P,Q)R(P, Q) and S(X,Y)S(X, Y).

Let E={⟨u⟩∣∃v ∃w ⟨u,v⟩∈R∧⟨v,w⟩∈S}E = \{\langle u \rangle \mid \exists v\, \exists w\ \langle u, v \rangle \in R \wedge \langle v, w \rangle \in S\} be a tuple relational calculus expression.

Which one of the following relational algebraic expressions is equivalent to EE?

Try it: multiple choice: exactly one correct option

Select one option
Wrong answer costs 2/3 mark in GATE.
Show answer and explanation

Answer: B (official GATE 2026 final answer key)

Concept used: Translate a shared variable between two relations into a join condition.

First step: vv is the second attribute of RR (Q) and the first attribute of SS (X), so the join is on R.Q=S.XR.Q = S.X.

Full step-by-step solution

Detailed working, common mistakes and linked mock tests will be available with a free GATEiit account. Log-in is coming soon.

Share this question

WhatsAppDownload image

Source: official GATE 2026 Session 1 CS question paper and final answer key, organised by IIT Guwahati. Question paper · Answer key

More Databases PYQs

PracticePractise Databases questions →Full paperAll GATE CSE 2026 Session 1 questions →