Let

**R = {A, B, C, D, E}**

and

F = { AB → C, A → D, D → E, AC → B }

Then compute {**AB} ^{+}** and

**{DC}**.

^{+}## A: Compute closure of AB ad DC

Given Relation:

**R = {A, B, C, D, E}**

Given Functional Dependencies:

AB → C

A → D

D → E

AC → B

## Closure of AB

{AB}^{+} = {AB} (axiom of reflexivity)

= {ABC} (by union rule & given FD: AB → C)

= {ABCD} (by union rule & given FD: A → D)

= {ABCDE} (by union rule & given FD: D → E)

Closure of DC

{DC}^{+} = {DC} (axiom of reflexivity)

= {DCE} (by union rule & given FD: D → E)

Hence,

Closure of AB, {AB}^{+} = {ABCDE}

and

Closure of DC, {DC}^{+} = {CDE}

Asked in Year

2022

Course

BBM

University

TU