Exercise #1
Data Selection: Designing a Dimensional Database
The TU Hotel chain is a small chain with properties throughout Pennsylvania, Arizona, Florida, and New
York. They have a central database to store and track guest reservations. In 2008, they put cafes in
many of their hotels, called “Café in the Hotel.” They have an order-tracking system that relays customer
orders from the wait staff to the kitchen.
TU Hotels would like to use the data they have collected to better understand the performance of their
hotels and cafes. They also have access to a database from the online review site
“HotelComplainer.com.”
Your task is to design two dimensional data marts using data from those three databases. You will plan
the star schema for each data mart by choosing the dimensions, facts, and attributes from the data
contained in those databases. The relational schemas of those databases are on the following page.
NOTE: You will not actually come up with answers to these questions since you have no data. You’ll
just be designing the star schemas that can address these questions about the business.
The questions to be addressed by each data mart are listed in the table below. You should include only
the data fields you need in each data mart, but the data marts can contain some of the same data (i.e.,
the same fields can appear in both data marts).
To complete the exercise, you’ll need to perform the following steps:
1) Identify the main business event for each data mart. This will be the fact.
Ask yourself, “What is the basic business event that generates the performance metric (revenue)?”
2) Identify the attributes associated with the fact.
Ask yourself, “How is the business event quantified (measured)?”
3) Identify the dimensions and their attributes.
Ask yourself, “What data characterizes the various aspects of that business event?”
4) Either sketch the star schema or make a list of the dimensions and the fact and their attributes. You
can use the examples in the slides as a guide.
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Data Mart 1: Hotel Performance
During which month are the most rooms
rented?
o Identify the “off season” (if any) for our
hotels in Arizona, Florida, Pennsylvania, and
New York
Which hotel generates the most (nonrestaurant) revenue?
What is the average length of stay in hotels
with 4.5 or more stars?
Do smokers stay longer than non-smokers?
For a given hotel, how many customers come
from out of state?
Data Mart 2: Restaurant Performance
 Which hotel restaurant generates the
most revenue?
 Do the best rated hotels generate more
restaurant revenue?
 What is the most frequently ordered item
in the Philadelphia metropolitan area?
Hotel Reservation Database
Countries
Country_code
Country_currency
Country_name
Hotels
Hotel_id
Country_code
Hotel_name
Hotel_address
Hotel_city
Hotel_zipcode
Hotel rooms
Room_number
Hotel_id
Room_type
Room_floor
Room types
Room_type_code
Room_standard_rate
Room_description
Smoking_YN
Room Bookings
Booking_id
Room_type_code
Hotel_id
Checkin_date
Number_of_days
Room_count
HotelComplainer Ratings
Database
(totally external company)
Ratings
Rating_id
Hotel_id
Date_of_stay
Star_rating
Review_text
Hotels
Hotel_id
Country_code
Hotel_name
Hotel_address
Hotel_city
Hotel_zipcode
Hotel Rating
Rating_id
Customer_id
Date_of_rating
Customer
Customer_number
Customer_name
Customer_address
Customer_city
Customer_zipcode
Customer_email
Hotel Amenities Lookup
Characteristic_id
Characteristic_description
Hotel Amenities
Characteristic_id
Hotel_id
Guest Bookings
Booking_id
Guest_number
Guests
Guest_number
Guest_firstname
Guest_lastname
Guest_address
Guest_city
Guest_zipcode
Guest_email
Café in the Hotel Database
(same company but database is not
connected to the hotel)
Customer
Customer_number
Customer_name
Customer_address
Customer_city
Customer_zipcode
Food item
Order number
Food_item_id
Order_date
Order_time
Order
Order_number
Customer_number
Hotel_id
Food_item_id
Order_date
Order_time
Table_number
Hotels
Hotel_id
Country_code
Hotel_name
Hotel_address
Hotel_city
Hotel_zipcode