Databases · Relational Model and SQL
Official IIT answer key · IIT Bombay · Audited Aug 2026
GATE CSE 2021 Set 1 Q23 · NAT · 1 mark
Key concept
No account needed
Sit 5 related Relational Model and SQLPYQs as a guest. We'll score the set and show which traps cost marks — sign in only if you want to save the run.
Topic notes
GATE tests the relational model across three interrelated formalisms: Relational Algebra (RA), Relational Calculus (TRC/DRC), and SQL. Questions evaluate core semantic equivalences, translation between declarative calculi and algebraic operators, table instance tracing (such as joins, group-by aggregations, and division), and corner cases like SQL three-valued logic, duplicate preservation, and safe TRC expressions.
Full Relational Model and SQL guide →A relation r(A, B) in a relational database has 1200 tuples. The attribute A has integer values ranging from 6 to 20, and the attribute B has integer values ranging from 1 to 20. Assume that the attributes A and B are independently distributed. The estimated number of tuples in the output of (A>10) (B=18)(r) is …
Topic-wise GATE CS PYQs with verified steps
Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.
