Demo database "Air Transport"

Authors Authors: Egor Rogov, Pavel Luzanov, Ilya Bashtanov

Photo by: Oleg Bartunov (Phu monastery, Bhrikuti summit, Nepal)

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Topics

Goals and Objectives

Subject Area and General Schema of the Demonstration

Database

Detailed Object Descriptions

Aviation

The demonstration database was created for the following purposes:

●

Self-directed study of the SQL query language

●

Development of textbooks, guides, and training courses on SQL;

●

Showcasing PostgreSQL features in articles and notes

When developing the demonstration database, we set out to achieve several

objectives:

●

The data schema should be simple enough to be understood without

additional explanations.

●

At the same time, the data schema should be sufficiently complex to

enable the creation of meaningful queries;

●

The database should be populated with realistic data that are engaging to

work with.

The demonstration database is licensed under the PostgreSQL license.

The database is available in three versions with different sizes. For example,

the large-volume database used in the query optimization course contains a

year's worth of flight data.

This topic covers the demo database version from 15.08.2017.

https://postgrespro.com/docs/postgresql/16/sql-copy

Overview

Bookings

# book_ref

Tickets

# ticket_no

* book_ref

Aircrafts

# aircraft_code

Seats

# aircraft_code

# seat_no

Ticket_flights

Flights

# ticket_no

# flight_id

Boarding_passes

Boarding Passes

# ticket_no

# flight_id

Flights

# flight_id

* departure_airport

* arrival_airport

* aircraft_code

Airports

# airport_code

The primary entity is booking (bookings).

A booking can include multiple passengers, each receiving their own ticket

(tickets).

A ticket may include one or more flights (ticket_flights). A ticket can include

multiple flights when there's no direct flight between the departure and

destination (a connecting flight) or when it's a round-trip ticket.

Each flight (flights) departs from one airport (airports) to another. Flights with

the same number have identical departure and arrival locations but different

departure dates.

When checking in for a flight, the passenger receives a boarding pass

(boarding_passes) that specifies the seat on the plane. A passenger can

only check in for the flight listed in their ticket Each flight and seat

combination is unique.

The number of seats and their allocation across service classes in an aircraft

depend on the specific aircraft model used for the flight. Each aircraft model

is assumed to have only one cabin layout.

The schema highlights only the columns that correspond to primary and

foreign keys. Next, we'll take a closer look at the main objects in the

demonstration database.

Bookings

A passenger books a ticket a month in advance for themselves and possibly

other passengers.

Booking number (alphanumeric combination)

Booking date

Total amount of tickets included in the booking

The passenger books a ticket for themselves and possibly others in

advance, with the booking date (book_date) up to a month before the flight.

Bookings are identified by a unique identifier (book_ref, a six-character

alphanumeric code).

The total_amount field stores the total cost of all passengers' flights included

in the booking.

Column | Type | Modifiers | Description

--------------+---------------+--------------+---------------------------

book_ref | char(6) | not null | Booking Number

book_date | timestamptz | not null | Booking date

total_amount | numeric(10,2) | not null | Total booking amount

Indexes:

PRIMARY KEY, btree (book_ref)

External References:

TABLE "tickets" FOREIGN KEY (book_ref) REFERENCES bookings(book_ref)

Tickets

A ticket is issued to a single passenger and may cover multiple flights.

Neither the passenger ID nor the name is permanent; it is not possible to

uniquely identify all tickets for the same passenger.

Ticket No.

Booking reference

Passenger ID (Document Number)

passenger_name | 16

Passenger Contact Details

The ticket contains a unique 13-digit number (ticket_no).

The ticket contains a passenger ID (passenger_id) — the passenger's

identity document number — along with their surname and name

(passenger_name) and contact information (contact_data).

Neither the passenger ID nor the name is permanent (e.g., a passport can

be replaced or a surname changed), making it impossible to uniquely

identify all tickets for the same passenger.

Column | Type | Modifiers | Description

----------------+-------------+--------------+-----------------------------

ticket_no | char(13) | not null | Ticket Number

book_ref | char(6) | not null | Booking Number

passenger_id | varchar(20) | not null | Passenger ID

passenger_name | text | not null | Passenger's Name

contact_data | jsonb | | Passenger's Contact Information

Indexes:

PRIMARY KEY, btree (ticket_no)

Foreign Key Constraints:

FOREIGN KEY (book_ref) REFERENCES bookings(book_ref)

External References:

TABLE "ticket_flights" FOREIGN KEY (ticket_no) REFERENCES tickets(ticket_no)

Flights

Ticket_flights

Flight connects tickets to flights

Ticket No.

Flight ID

class of service

Flight Cost

A flight links a ticket to a flight, identified by the ticket and flight numbers.

For each flight, the cost (amount) and service class (fare_conditions) are

specified.

Column | Type | Modifiers | Description

-----------------+---------------+--------------+---------------------

ticket_no | char(13) | not null | Ticket Number

flight_id | integer | not null | Flight ID

fare_conditions | varchar(10) | not null | Class of service

amount | numeric(10,2) | not null | Flight Cost

Indexes:

PRIMARY KEY, btree (ticket_no, flight_id)

Check Constraints:

CHECK (amount >= 0)

CHECK (fare_conditions IN ('Economy', 'Comfort', 'Business'))

Foreign Key Constraints:

FOREIGN KEY (flight_id) REFERENCES flights(flight_id)

FOREIGN KEY (ticket_no) REFERENCES tickets(ticket_no)

External References:

TABLE "boarding_passes" FOREIGN KEY (ticket_no, flight_id)

REFERENCES ticket_flights(ticket_no, flight_id)

Flights

The flight operates on schedule between airports.

Natural key: flight number and departure date, but a surrogate key is used.

Flight ID

flight number

scheduled departure and arrival

actual departure and arrival

Departure and arrival airports

Flight status

filter: (aircraft_code = f.aircraft_code)

A flight connects the departure and arrival airports. If there's no direct flight,

the ticket includes multiple flights.

Column | Type | Modifiers | Description

---------------------+-------------+--------------+----------------------------

flight_id | integer | not null | Flight ID

flight_no | char(6) | not null | Flight Number

scheduled_departure | timestamptz | not null | Scheduled departure time

scheduled_arrival | timestamptz | not null | Scheduled Arrival Time

departure_airport | char(3) | not null | Departure Airport

Arrival Airport

status | varchar(20) | not null | Flight Status

aircraft_code | char(3) | not null | Aircraft code (IATA)

Actual Departure Time

actual_arrival | timestamptz | | Actual Arrival Time

Indexes:

PRIMARY KEY, btree (flight_id)

UNIQUE CONSTRAINT, btree (flight_no, scheduled_departure)

Check Constraints:

CHECK (scheduled_arrival > scheduled_departure)

CHECK ((actual_arrival IS NULL)

OR ((actual_departure IS NOT NULL AND actual_arrival IS NOT NULL)

AND (actual_arrival > actual_departure)))

CHECK (status IN ('On Time', 'Delayed', 'Departed',

'Arrived', 'Scheduled', 'Cancelled'))

Foreign Key Constraints:

FOREIGN KEY (aircraft_code) REFERENCES aircrafts_data(aircraft_code)

FOREIGN KEY (arrival_airport) REFERENCES airports_data(airport_code)

FOREIGN KEY (departure_airport) REFERENCES airports_data(airport_code)

Airports

The city is not stored in a separate table

Implementation: Multilingual view on airports_data

airport code

airport name

city

Airport coordinates (longitude and latitude)

timezone

The airport is identified by a three-letter code (airport_code) and is known as

(airport_name).

Cities are not represented as a separate entity, but a "city" field has been

introduced to help locate airports within the same city. This view also

includes the airport's coordinates (coordinates) and time zone (timezone).

The airport_name and city field values depend on the language set in the

configuration parameter bookings.lang.

Column | Type | Modifiers | Description

--------------+---------+--------------+---------------------------------------

airport_code | char(3) | not null | Airport code

airport_name | text | not null | Description: Airport Name

city | text | not null | City

Description: Airport coordinates

timezone | text | not null | Airport Time Zone

View Definition:

SELECT ml.airport_code,

ml.airport_name ->> lang() AS airport_name,

ml.city ->> lang() AS city,

ml.coordinates,

ml.timezone

FROM airports_data ml;

Aircrafts

aircraft models operating flights

Implementation: a multilingual view of aircrafts_data

filter: (aircraft_code = f.aircraft_code)

aircraft model

Maximum flight range (km)

Each aircraft model is uniquely identified by its three-digit code

(aircraft_code). Additionally, the model (model) and maximum flight range in

kilometers (range) are specified.

The model field's value is determined by the selected language specified in

the configuration parameter bookings.lang.

Column | Type | Modifiers | Description

---------------+---------+--------------+-----------------------------------

aircraft_code | char(3) | not null | Aircraft code (IATA)

model | text | not null | Aircraft Model

range | integer | not null | Maximum flight range (km)

View Definition:

SELECT ml.aircraft_code,

ml.model ->> lang() AS model,

ml.range

FROM aircrafts_data ml;

Seats

Seats determine the cabin layout

All aircraft of the same model share the same cabin layout

filter: (aircraft_code = f.aircraft_code)

seat number

class of service

Seats determine the cabin layout for each model. Each seat is identified by

its seat number (seat_no) and is assigned a class of service

(fare_conditions) – Economy, Comfort, or Business.

Column | Type | Modifiers | Description

-----------------+-------------+--------------+--------------------

aircraft_code | char(3) | not null | Aircraft code (IATA)

seat_no | varchar(4) | not null | Seat Number

fare_conditions | varchar(10) | not null | Class of service

Indexes:

PRIMARY KEY, btree (aircraft_code, seat_no)

Check Constraints:

CHECK (fare_conditions IN ('Economy', 'Comfort', 'Business'))

Foreign Key Constraints:

FOREIGN KEY (aircraft_code)

REFERENCES aircrafts(aircraft_code) ON DELETE CASCADE

Boarding Passes

Boarding_passes

The boarding pass is issued when checking in for the flight.

Ticket No.

Flight ID

boarding pass number (in the order of registration)

seat number

Passengers can register for a flight up to a day in advance of the scheduled

departure date, and they are then issued a boarding pass.

Boarding passes are assigned sequential numbers (boarding_no) according

to the order in which passengers register for the flight. This number is

unique only within the flight. The boarding pass includes the seat number

(seat_no).

Column | Type | Modifiers | Description

-------------+------------+--------------+--------------------------

ticket_no | char(13) | not null | Ticket Number

flight_id | integer | not null | Flight ID

boarding_no | integer | not null | Boarding Pass Number

seat_no | varchar(4) | not null | Seat Number

Indexes:

PRIMARY KEY, btree (ticket_no, flight_id)

UNIQUE CONSTRAINT, btree (flight_id, boarding_no)

UNIQUE CONSTRAINT, btree (flight_id, seat_no)

Foreign Key Constraints:

FOREIGN KEY (ticket_no, flight_id)

REFERENCES ticket_flights(ticket_no, flight_id)

Multilingual Support

Configuration parameter

bookings.lang

Tables to store multilingual names

airports_data

aircrafts_data

The language for displaying city, airport, and aircraft model names is set via

the configuration parameter bookings.lang. The demo base contains names

in Russian (ru) and English (en).

You can independently expand the language support by addingnames in any

language to the rows of the airports_data and aircrafts_data tables.

Takeaways

The demo database's schema is simple yet enables the creation

of complex and intriguing queries.

The data in the demo database is similar to real data.

The demo database can be used for learning SQL, showcasing

PostgreSQL features, and other purposes.

Practice

Write a few queries against the demo database.

1. How many people are included in a single booking?

2. Which cities cannot be reached from Moscow without transfers?

3. Which airplane model operates the most flights, and which

operates the fewest?

4. And which aircraft model carried the most passengers?

1. The result will be two columns:

Number of people per booking

Booking count