$3\mathrm{.}4.$ Step $4$ of the logical design phase involves mapping binary relations. The DBMS team

successfully mapped one$-$to$-$many $(1$:${?}^{**})$ and many$-$to$-$many $(**$:$**)$ relationships. The team

will now attempt to map the one$-$to$-$one $(1$:$1)$ relationship between the

POS$\_$CHECKOUT$\_$STUDENT NUMBER and SHIFT$\_$ALLOCATION$\_$STUDENT NUMBER

entities. This $1$:$1$ relationship is informed by the business rule that only one POS device can

be checked out for a shift. A shift can be allocated to $1$ and a maximum of $4$ parking area

employees. Each of the four employees assigned to a parking attendant services shift can

check out a POS device based on the notion that each person is patrolling a different area

of the parking area. So$,$ the relationship between SHIFT$\_$ALLOCATION$\_$STUDENT NUMBER

and POS$\_$CHECKOUT$\_$STUDENT NUMBER is a mandatory one. Conversely, in the case of

shifts related to car cleaning services, only one employee can check out a POS device on

behalf of the group of four ${?}^{10}.$ Therefore, the POS$\_$CHECKOUT$\_$STUDENT NUMBER to

SHIFT$\_$ALLOCATION$\_$STUDENT NUMBER relationship is optional. Based on the principles

of relational calculus, the service price amount is divided by four.

$3\mathrm{.}4\mathrm{.}1.$ Create an ERD that comprise multiplicities, association names and association

directions to illustrate the $1$:$1$ relationship between POS$\_$CHECKOUT$\_$STUDENT

NUMBER and SHIFT$\_$ALLOCATION$\_$STUDENT NUMBER. Examine Coronel et al$.\text{'}$s

${?}^{10}$ A vehicle is cleaned by four people. For example, one person is responsible for washing the car with

cleaning foam and a high$-$pressure sprayer, another person will do the drying, someone will do the

vacuuming, and so forth.

INF$3703-$ASSIGNMENT $2$

$(2020,$ p$.598)$ mapping of the ${?}^{}1$:$1$ relationship $...$ between the entities LECTURER

and SCHOOL" to guide you.

$(6)+(22)=(10)$

$3\mathrm{.}4\mathrm{.}2.$ Formulate the relations of both the POS$\_$CHECKOUT$\_$STUDENT NUMBER and

SHIFT$\_$ALLOCATION$\_$STUDENT NUMBER entities.

$(2)+(4)=(6)$

$3\mathrm{.}5.$ Step $5$ of the logical design phase involves mapping ternary relations $($see page $187).$

Examine the ternary relationship between the entities HOM, POS$\_$DEVICE and

SHIFT$\_$ALLOCATION as illustrated in the simplified ERD below.

$3\mathrm{.}5\mathrm{.}1.$ Formulate the business rules that underpin the ternary relationship.

$(32)=(6)$