Data Abstractions

This document has three major sections:

• The ERD diagram
• The ERD attribute entites
• The Data Dictionary

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The ERD diagram

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The ERD entity and relationship attributes:

Entities

Employee	Guest	Invoice	Fee
employee ID	guest ID	invoice number	item number
employee first name	guest first name	date	fee description
employee last name	guest last name	time	fee cost
security type	address	payment method
password	city	total bill
	province/state	food order
	country	movie order
	credit card #	telephone bill
	credit card exp.	misc. charges
	credit card name	hotel tax
	type of photo ID	GST
	discount name	paid
	discount rate
	phone number
Room Type	Credit Card	Security	Room
room type name	credit card type	security type	room number
room rate	credit card name	security name	room type id
room type id

Weak Entity

Room Service
time ordered
date ordered
time to deliver
date to deliver
room number
employee ID
comments
item number

Relationships

In Room	Booked by	Sign-in by	Sign-out by
guest ID	guest ID	guest ID	guest ID
room number	employee ID	employee ID	employee ID
confirmation no.	room number	room number	room number
arrival date
duration of stay
check out date
no. of occupants
Security for	Credit Card of	Room type of	Charged to
employee ID	guest ID	room number	guest ID
security type	credit card type"	room type	invoice number
Billed for	Issued by	Fee of	Delivered by
invoice number	invoice number	item number	employee ID
room number	employee ID	room number	room number
		date ordered	date ordered
		time ordered	time ordered

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The Data Dictionary for the ERD:

address = string
* A non key attribute of entity Guest, having a maximum length of 256
* characters. This attribute is not needed when making a reservation
* to stay at the hotel.
* Data flow in DFD's

arrival date = date
* A non key attribute of the relationship In Room. The room booked
* in date.
* Data flow in DFD's

Billed for = @invoice number + @room number
* This is a 1:Mc relationship that relates an instance of entity
* Invoice to an instance of entity Room. This indicates which room
* an invoice is for.

Booked by = @guest ID + @employee ID + @room number
* This is a 1:Mc:Mc relationship. It relates an instance of entity
* Guest to an instance of entity Employee and entity Room. It
* indicates which employee booked the room for the guest.

Charged to = @guest ID + @invoice number
* This is a 1:M relationship that relates an instance of entity
* Invoice to an instance of entity Guest. This relationship indicates
* who an invoice should be charged to.

check out date = date
* A non key attribute of the relationship In Room. The date the
* occupant of the room will be checking out.
* Data flow in DFD's

city = string
* A non key attribute of entity Guest. Maximum length is 256
* characters. Allowed to be null when booking.
* Data flow in DFD's

comment = string
* A non key attribute of weak entity Room Service. Can be up to 100
* characters long. It is used to provide an special requests or remark.
* Data flow in DFD's

confirmation number = integer
* Identifies a unique reservation. It is a non key attribute of the
* relationship In Room.

country = string
* A non key attribute of entity Guest. Maximum 50 characters long.
* Allowed to be null when booking.
* Data flow in DFD's

Credit Cards = {Credit Card}
* Data Store in DFD's. Corresponds to the entity "Credit Card".

credit card = {Credit Card}
* Data flow in DFD's. Corresponds to an instance from the data store "Credit Cards".

credit cards = {Credit Card}
* Data flow in DFD's. Corresponds to zero or more instances of the data store "Credit Cards".

Credit Card = @credit card type + @credit card name
* A entity which contains a credit card name and a unique integer
* identifying the credit type name.

Credit Card of = @guest ID + @credit card type
* This is a 1:Mc relationship relates an instance of Guest to an
* instance of Credit Card. It indicates the type of credit card.

credit card expiry = date
* A non key attribute of entity Guest. This is the expiry date of
* the credit card.
* Data flow in DFD's

credit card name = name
* A non key attribute of entity Guest. This is the name that is
* on the physical credit card.
* Data flow in DFD's

credit card number = string
* A non key attribute of entity Guest. Maximum length is 256
* characters.
* Data flow in DFD's

credit card type = integer
* A key attribute of entity Credit Card. It uniquely identifies each
* credit card type.
* Data flow in DFD's

date = string
* A typed defined as a string of 10 characters, holding a date.
* it is of the format YYYY/MM/DD
* Data flow in DFD's

date ordered = date
* A key attribute of the weak entity Room Service. It gives the
* date of when the particular room service was requested
* Data flow in DFD's

date to deliver = date
* A non key attribute of the weak entity Room Service. Informing
* the hotel, as to when the particular requested room service is
* to be provided/delivered
* Data flow in DFD's

Delivered by = @employee ID + @room number + @date ordered + @time ordered
* This is a 1:Mc relationship that relates an instance of the weak
* entity Room Service to an instance of entity Employee. It indicates
* which employee delivered the room service.

discount name = string
* A non key attribute of entity Guest. Maximum 256 characters
* long. Allows the user to enter the reason for giving discount
* Data flow in DFD's

discount rate = flate
* A non key attribute of entity Guest. Has 2 decimal places
* Data flow in DFD's

duration of stay = integer
* A non key attribute of the relationship In Room. It is 3 digits
* long, holding the number of days the guest will stay for. Its
* from 1 to 999 days.
* Data flow in DFD's

employee = {Employee}
* Data flow in DFD's. Corresponds to single instance in Employee Data Store

employees = {Employee}
* Data flow in DFD's. Corresponds to zero or more instances of the entity "Employee"

Employee = @employee ID + employee first name + employee last name + security type + password
* This entity contains information of all employees working for the
* hotel.

Employees = {Employee} * Data Store in DFD's. Corresponds to zero or more instances of the
* entity "Employee".

employee first name = name
* A non key attribute of entity Employee, which contain employee's
* first name
* Data flow in DFD's

employee id = integer
* A key attribute of entity employee. It uniquely identifies each
* instance of entity employee.
* Data flow in DFD's

employee last name = name
* A non key attribute of entity Employee, which contain employee's
* last name.
* Data flow in DFD's

Fees = {Fee}
* Data store in DFD's. Corresponds to the entity "Fee".

fee = {Fee}
* Data flow in DFD's. Corresponds to an instance in data store "Fees".

fees = {Fee}
* Data flow in DFD's. Corresponds to zero or more instances in data store "Fees".

Fee = @item number + fee description + fee cost
* This entity stores the different room services offered (ie. food
* item, wake up calls). It contains a description and cost for
* each item.

Fee of = @item number + @room number + @date ordered + @time ordered
* This is a 1:Mc relationship that relates an instance of the weak
* entity Room Service to an instance of entity Fee. It indicates
* which service was ordered and what it will cost.

fee description = string
* This item describes the type of fee. it is a string 50 characters
* long.
* Data flow in DFD's

fee cost = real
* This item gives the cost for a fee. It has a range of 0.00 to no
* upper bound.
* Data flow in DFD's

food order = float
* A non key attribute of Invoice. Carries up to 2 decimal places.
* This is the total sum for the food ordered.
* Data flow in DFD's

Guests = {Guest}
* Data Store in DFD's. Corresponds to the entity "Guests".
Guest = @guest ID + guest first name + guest last name + address + city + province/state + postal code/zip code + photo ID + discount name + discount percentage + phone number
* Is an entity that stores all the information pertaining to a guest
* staying at the hotel. Most of the information is obtained when a
* guest checks into the hotel.

guest = {Guest}
* Data flow in DFD's. Corresponds to an instance in Data Store "Guests".

* Data flow in DFD's. Corresponds to zero or more instances in Data Store "Guests".

guest ID = integer
* A key attribute of the entity Guest. It is 6 digits long, and has
* a fixed format.
* Data flow in DFD's

guest first name = name
* A non key attribute of entity Guest, gives first name of a person
* staying at the hotel.
* Data flow in DFD's

guest last name = name
* A non key attribute of entity Guest, gives last name of a person
* staying at the hotel.
* Data flow in DFD's

GST = float
* A non key attribute of entity Invoice. Carries up to 2 decimal
* places. GST charged.
* Data flow in DFD's

hotel tax = float
* A non key attribute of Entity Invoice. Carries up to 2 decimal
* places. Stores the tax (percentage) for hotel usage.
* Data flow in DFD's

Invoices = {Invoice}
* Data store in DFD's. Corresponds to the entity "Invoice".

invoice = {Invoice}
* Data flow in DFD's. Corresponds to an instance from Data Store "Invoices"

invoices = {Invoice}
* Data flow in DFD's. Corresponds to zero or more instances from Data Store "Invoices"

Invoice = @invoice number + room number + employee ID + date + time + paid + payment method + total bill + food orders + movie ordering + telephone vill + miscellaneous charge + hotel tax + GST + guest ID
* This entity holds the information contained on an invoice, which
* is issued when the guest checks out.

invoice number = integer
* An key attribute of entity Invoice. It uniquely identifies each
* instance of entity Invoice. Its a 6 digit number that ranges from
* 1 to the number of instances of entity Invoice.
* Data flow in DFD's

In Room = @guest ID + @room number + confirmation number + arrival date + duration of stay + check out dat + number of occupants
* This is a relationship between entities Guest and Room

Issued by = @invoice number + @employee ID
* This is a 1:Mc relation that relates an instance of entity Invoice
* to an instance of entity Employee. This relationship indicates
* which employee generated an invoice.

Item number = integer
* A key attribute of entity Fee. It identifies each fee with a
* unique id. Its bounded by the number of instances of Fee. It is
* represented by a 5 digit number.
* Data flow in DFD's

miscelaneous charge = float
* A non key attribute of entity Invoice. Carries up to 2 decimal
* places. The sum of cost for anything damaged or any thing charged
* to the guest that is not on the fee list.
* Data flow in DFD's

movie ordered = float
* A non key attribute of entity Invoice. Carries up to 2 decimal
* places. The sum for the movie ordered.
* Data flow in DFD's

name = string
* A type, defined to have a maximum length of 256 characters,
* contains no space, only alphabetical characters allowed with
* exception of apostrophe.
* Data flow in DFD's

number of occupants = integer
* A non key attribute of relationship In Room. It is 1 digit long,
* representing the number of occupants in a room. Bounded between
* the values of 1 and 9
* Data flow in DFD's

paid = ["true" | "false"]
* A non-key attribute of entity Invoice. It indicates wether the Invoice
* has been paid or not.

password = string
* A non key attribute of entity Employee, which must be at least 8
* characters in length and maximum 11 characters. Every employee,
* has a password, and to access the system, it is required that
* they enter one
* Data flow in DFD's

payment method = string
* A non key attribute of entity Invoice. Denotes the method of
* payment
* Data flow in DFD's

phone number = string
* This is a non-key attribute of entity Guest. It contains the contact
* phone number for the guest. Its of the form XXX-XXX-XXXX. The first
* three X's being the area code.
* Data flow in DFD's

province/state = string
* A non key attribute of entity Guest. Maximum length is 256
* characters. Allowed to be null when booking. Length given is
* to accomodate full name rather than abbreviations.
* Data flow in DFD's

postal code/zip code = string
* A non key attribute of entity Guest. Maximum length is 256
* characters. Allowed to be null when booking
* Data flow in DFD's

Rooms = {Room}
* Data Store in DFD's. Corresponds to the Entity "Room".

room = {Room}
* Data flow in DFD's. Corresponds to an instance from Data Store "Rooms".

rooms = {Room}
* Data flow in DFD's. Corresponds to zero or more instances from Data Store "Rooms".

Room = @room number + room type
* This entity represents a room in the hotel. It contains a room
* number and the room type.

room number = integer
* This key attribute of entity Room contains the room number.
* Its a 3 digit number ranging from 1 to 999.
* Data flow in DFD's

room rate = real
* This non-key attribute of entity Room Type indicates the cost of
* the room type for one night. Its ranges from a value of 0.0 to
* 1000.0.
* Data flow in DFD's

Room Service = @room number + @date ordered + @time ordered +
comment + date to deliver + employee ID + item number + time to deliver * A weak entity containing all the services requested by a room,
* ie. wake up calls, food orders...

Room Type = @room type id + room name + room rate
* This entity contains the room type name and cost for each room type.

Room Types = {Room Type}
* Data Store in DFD's. Corresponds to the Entity "Room Type".

room type = {Room Type}
* Data flow in DFD's. Corresponds to an instance from Data Store "Room Types".

room types = {Room Type}
* Data flow in DFD's. Corresponds to zero or more instances from Data Store "Room Types".

room type id = integer
* This key attribute of entity Room Type uniquely identifies each
* instance of entity Room Type. Its a 2 digit number from 1 to 99.
* Data flow in DFD's

room type name = string
* This non-key attribute of entity Room Type gives the name for
* each room type. Its a string of 50 characters in lenght.
* Data flow in DFD's

Room Type of = @room number + @room type
* This is a 1:Mc relationship that relates an instance of Room
* to an instance of Room Type. This relationship gives the room
* type for each room.

Securities = {Security}
* Data Store in DFD's. Corresponds to the Entity "Security".

security = {Security}
* Data flow in DFD's. Corresponds to an instance from Data Store "Security".

securities = {Security}
* Data flow in DFD's. Corresponds to zero or more instances from Data Store "Security".

Security = @security type + security name
* This entity contains a security level. Each security
* level is given a unique id and a name. All employee's are assigned a
* security level.

Security for = @employee ID + @security
* This is a relationship that relates an instance of Employee to an
* instance of Security. The relationship is 1:Mc. It indicates the
* security level for each employee.

security name = string
* A non key attribute of entity Security. It can be up to 25
* characters long, that is descriptive of employee's job
* classification.
* Data flow in DFD's

security type = integer
* A key attribute of the entity Security. The value of security type
* is bounded byt he number of items in the table, maximum value will
* be 100.
* Data flow in DFD's

Sign-in by = @guest ID + @employee ID + @room number
* This is a 1:Mc:Mc relationship, that relates an instance of entity
* Guest to an instance of entity Employee and entity Room. It
* indicates which employee signed a guest into a room.

Sign-out by = @guest ID + @employee ID + @room number
* This is a 1:Mc:Mc relationship, that relates an instance of entity
* Guest to an instance of entity Employee and entity Room. It
* indicates which employee signed a guest out of a room.

telephone bill = float
* A non key attribute of entity Invoice. Carries up to 2 decimal
* places. This charge is not calculated by the system, but rather is
* provided by an outside source.
* Data flow in DFD's

time ordered = time
* A key attribute of weak entity Room Service. Holds the time at
* which a particular room service was requested.
* Data flow in DFD's

time to deliver = time
* A non key attribute of weak entity Room Service. Informing the hotel as
* to what time the particular room service is to be provided/delivered
* Data flow in DFD's

time = string
* A type defined as a string of 8 characters, holding a time. It is
* of the format HH:MM:SS.
* Data flow in DFD's

total bill = float
* A non key attribute of entity Invoice. Carries up to 2 decimal
* places. This is the final and total sum amount for which the
* departing guest must pay.
* Data flow in DFD's

type of photo ID = string
* A non key attribute of entity Guest. Maximum 256 characters in
* length. Consisting of a description of the kind of ID and could
* include number that identifies the card as well. It is obtained
* when guest checks in to hotel.
* Data flow in DFD's