Database Systems and KE $-2023\mathrm{.}05\mathrm{.}17.$

II$.$ Part: Tasks

Define Functional Dependencyl

List the only the Armstrong axioms and state the below statement using only theml

$\{WxY,xZ,ZWY\}|=\{xY\}|$

$($a$)$ In the database context, what do we mean by redundant data? $[1$ point$]$

$($b$)$ Why might it be a good idea to have redundant data in a database? $[2$ points$]$

$($c$)$ Why might it be a bad idea to have redundant data in a database? $[2$ points$]$

The table given below lists custorner$/$car hire data. Each customer may hire cars from various

outlets throughout Glasgow. A car is registered at a particular outlet and can be hired out to a

customer on a given date.

a$)$ Identify the functional dependencies represented by the data shown in the table.

State any assumptions you make about the data.

$(3$ points$)$

b$)$ Using the functional dependencies identified in part $($a$),$ describe and illustrate the process of

normalization by converting that Table to Third Normal Form $(3$NF$)$ relations. Identify the

primary and foreign keys in your $3$NF relations.

$(4$ points$)$

c$)$ Sketch an Entity $-$ Relationship model for the data shown in Table. Show all the entities,

relationships, and attributes

$(4$ points$)$