Step $4$ of the logical design phase involves mapping binary relations. The DBMS team successfully mapped one$-$to$-$many $(1$:$)$ 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 ca 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 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