The GATE Grind

GATE 2025 CS (CS1) – Question 47

Databases · ER-Model and Database Architecture · 2 marks · Multiple select

Consider a relational schema $team(name, city, owner)$, with functional dependencies $\{name \rightarrow city,\ name \rightarrow owner\}$.

The relation $team$ is decomposed into two relations, $t1(name, city)$ and $t2(name, owner)$. Which of the following statement(s) is/are TRUE?

  1. The relation $team$ is NOT in BCNF.
  2. The relations $t1$ and $t2$ are in BCNF.
  3. The decomposition constitutes a lossless join.
  4. The relation $team$ is NOT in 3NF.

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Correct answer: (B) The relations $t1$ and $t2$ are in BCNF.; (C) The decomposition constitutes a lossless join.

Explanation

name is a candidate key of team, so team is already in BCNF and 3NF. In t1 and t2 the only FD has name as key, so both are in BCNF. The common attribute name is a key of both, so the join is lossless.