Question $5$

You are asked to design the database structure for an international hotel chain. The following is a list of requirements for the design that you have to model.

A hotel contains a set of rooms, each with a room number. Different hotels can have rooms with the same number but within a hotel the number is unique.

The hotel chain owns many hotels

Each hotel has the following attributes: a unique building ID $($bID$),$ a name that is not necessarily unique, country, state, city, and street address.

For each room, we associate with it the maximum number of possible occupants.

A room can be occupied by hotel guests between a given check$-$in and check$-$out date.

Each guest has a guest ID $($gID$)$ and a name that is not necessarily unique.

The guest who pays for the room is designated as the payer.

This person has an attribute, creditCardNumber, associated with him$/$her for the credit card that is used to pay for the stay.

Guests are modeled using an entity set guest. They are related to room via a relationship reservedBy. What is a good way to model payer? What is$/$are the attribute$($s$)$ for payer? What is$/$are its key$($s$)?$

$1$ point

As an entity set payer connected to guest using a many$-$to$-$one relationship paid$\_$by$.$ Add creditCardNumber as an attribute to payer. Attributes: creditCardNumber. Key: creditCardNumber.

As a role payer of guest. Add creditCardNumber as an attribute to guest. Attributes: gID, name, creditCardNumber. Key: gID, creditCardNumber.

As a role payer of guest. Add creditCardNumber as an attribute to guest. Attributes: gID, name, creditCardNumber. Key: gID.

As a subclass of guest with creditCardNumber as an attribute. Attributes: gID, name, creditCardNumber. Key: gID, creditCardNumber.

As a subclass of guest with creditCardNumber as an attribute. Attributes: gID, name, creditCardNumber. Key: gID.

As an entity set payer connected to guest using a one$-$to$-$many relationship paid$\_$by$.$ Add creditCardNumber as an attribute to payer. Attributes: creditCardNumber. Key: creditCardNumber.