Given a relational schema, R(A, B, C), and set of functional dependencies over R, F = {A → B, AB → C}. prove or disprove the following statements. (a) A is a superkey for R. (b) A is a minimal key for R. (c) Let K be a minimal key for R. Then KU{A} is a superkey for R.

Given a relational schema, R(A, B, C), and set of functional dependencies over R, F = {A → B, AB → C}. prove or disprove the following statements. (a) A is a superkey for R. (b) A is a minimal key for R. (c) Let K be a minimal key for R. Then KU{A} is a superkey for R.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Question

Given a relational schema, R(A, B, C), and set of functional dependencies over R,
F = {A → B, AB → C}. prove or disprove the following statements.
%3D
(a) A is a superkey for R.
(b) A is a minimal key for R.
(c) Let K be a minimal key for R. Then KU{A} is a superkey for R.
(d) BC is a superkey for R.
(e) If B satisfies the UNIQUE constraint, then so does A.
(f) If A safisfies the UNIQUE constraint, then so does B.

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