航空公司数据库设计
背景
通过学习航空公司数据库设计，学习PostgreSQL的使用。
这个DEMO来自postgrespro：
https://postgrespro.com/docs/postgrespro/10/demodb-bookings.html
加载航空公司数据
可以任选一个数据集，使用pg_restore还原到你的PostgreSQL数据库中，还原时，会新建一个demo数据库，数据导入demo数据库中。
demo-small.zip (21 MB) — flight data for one month (DB size is about 300 MB)
demo-medium.zip (62 MB) — flight data for three months (DB size is about 700 MB)
demo-big.zip (232 MB) — flight data for one year (DB size is about 2.5 GB)
航空公司数据库schema
描述
主要的实体是bookings(demo库里的schema)，所有的对象都在这里。
一个booking可以包括几名乘客，每位乘客一张票。票有一个独特的号码，包括乘客的信息。因此，乘客不是一个单独的实体。乘客的姓名和身份证件号码都可以随时间变化，因此不可能唯一地识别某一个人的所有票; 为了简单起见，假设所有乘客都是唯一的。
机票包括一个或多个飞行段(ticket_flights)。如果在起飞点和目的地之间没有直达航班，或者是往返机票，可以将几个航班段包括在单张机票中。尽管在模式中没有约束，但是假设预订中的所有机票都有相同的航班段。
每个航班(flights)从一个机场飞往另一个机场(airports)。同一航班号的航班有相同的出发点和目的地，但不同的起飞日期。
在飞行登记时，乘客需要打印登机牌(boarding_pass)，包含座位号码信息。旅客可以办理登机手续，只有在这趟航班被列入ticket的情况下才能办理登机手续。飞行座椅的组合必须是唯一的，以避免为同一个座位签发两个登机牌。
飞机上的座位(seats)和不同的旅行等级之间的分配取决于飞机(aircrafts)的飞行模式。假设每个飞行器模型只有一个舱位结构。数据库中不检查登机牌上的座位号是否有相应的飞机座位(这样的验证可以使用表触发器，或者在应用程序中调度)。
Schema Objects
大量的使用了JSON类型，视图。
Name | Type | Small | Medium | Big | Description
-----------------+---------------+--------+--------+--------+-------------------------
aircrafts | view | | | | Aircraft
aircrafts_data | table | 16 kB | 16 kB | 16 kB | Aircraft (translations)
airports | view | | | | Airports
airports_data | table | 56 kB | 56 kB | 56 kB | Airports (translations)
boarding_passes | table | 31 MB | 102 MB | 427 MB | Boarding passes
bookings | table | 13 MB | 30 MB | 105 MB | Bookings
flights | table | 3 MB | 6 MB | 19 MB | Flights
flights_v | view | | | | Flights
routes | view | | | | Routes
seats | table | 88 kB | 88 kB | 88 kB | Seats
ticket_flights | table | 64 MB | 145 MB | 516 MB | Flight segments
tickets | table | 47 MB | 107 MB | 381 MB | Tickets
对象解释
1、视图bookings.aircrafts
包括飞机编号，飞机机型，飞机最大飞行公里数。
Column | Type | Modifiers | Description
---------------+---------+--------------+-----------------------------------
aircraft_code | char(3) | not null | Aircraft code, IATA
model | text | not null | Aircraft model
range | integer | not null | Maximal flying distance, km
View definition:
SELECT ml.aircraft_code,
ml.model ->> lang() AS model,
ml.range
FROM aircrafts_data ml;
2、表bookings.aircrafts_data
机型使用JSON存储，包含更多内容。
Column | Type | Modifiers | Description
---------------+---------+--------------+-----------------------------------
aircraft_code | char(3) | not null | Aircraft code, IATA
model | jsonb | not null | Aircraft model
range | integer | not null | Maximal flying distance, km
Indexes:
PRIMARY KEY, btree (aircraft_code)
Check constraints:
CHECK (range > 0)
Referenced by:
TABLE "flights" FOREIGN KEY (aircraft_code)
REFERENCES aircrafts_data(aircraft_code)
TABLE "seats" FOREIGN KEY (aircraft_code)
REFERENCES aircrafts_data(aircraft_code) ON DELETE CASCADE
3、视图bookings.airports
机场信息，机场代码，机场名，城市，经纬度，时区。
Column | Type | Modifiers | Description
--------------+---------+--------------+--------------------------------------------
airport_code | char(3) | not null | Airport code
airport_name | text | not null | Airport name
city | text | not null | City
coordinates | point | not null | Airport coordinates (longitude and latitude)
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;
4、表bookings.airports_data
机场代码，机场名（JSON存储），城市（JSON存储），经纬度，时区。
Column | Type | Modifiers | Description
--------------+---------+--------------+--------------------------------------------
airport_code | char(3) | not null | Airport code
airport_name | jsonb | not null | Airport name
city | jsonb | not null | City
coordinates | point | not null | Airport coordinates (longitude and latitude)
timezone | text | not null | Airport time zone
Indexes:
PRIMARY KEY, btree (airport_code)
Referenced by:
TABLE "flights" FOREIGN KEY (arrival_airport)
REFERENCES airports_data(airport_code)
TABLE "flights" FOREIGN KEY (departure_airport)
REFERENCES airports_data(airport_code)
5、表bookings.boarding_passes
CHECK IN信息，机票ID，飞行ID，登机口，座位号。
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)
6、表bookings.bookings
一条记录代表一趟行程，日期，该行程所有机票加起来的金额。
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 cost
Indexes:
PRIMARY KEY, btree (book_ref)
Referenced by:
TABLE "tickets" FOREIGN KEY (book_ref) REFERENCES bookings(book_ref)
7、表bookings.flights
航班信息，编号，状态等。
Column | Type | Modifiers | Description
---------------------+-------------+--------------+-----------------------------
flight_id | serial | 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 | Airport of departure
arrival_airport | char(3) | not null | Airport of arrival
status | varchar(20) | not null | Flight status
aircraft_code | char(3) | not null | Aircraft code, IATA
actual_departure | timestamptz | | 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(aircraft_code)
FOREIGN KEY (arrival_airport)
REFERENCES airports(airport_code)
FOREIGN KEY (departure_airport)
REFERENCES airports(airport_code)
Referenced by:
TABLE "ticket_flights" FOREIGN KEY (flight_id)
REFERENCES flights(flight_id)
8、表bookings.seats
座位信息
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 | Travel class
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
9、表bookings.ticket_flights
机票与航班关联的信息
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 | Travel class
amount | numeric(10,2) | not null | Travel 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)
Referenced by:
TABLE "boarding_passes" FOREIGN KEY (ticket_no, flight_id)
REFERENCES ticket_flights(ticket_no, flight_id)
10、表bookings.tickets
机票销售记录。
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 name
contact_data | jsonb | | Passenger contact information
Indexes:
PRIMARY KEY, btree (ticket_no)
Foreign-key constraints:
FOREIGN KEY (book_ref) REFERENCES bookings(book_ref)
Referenced by:
TABLE "ticket_flights" FOREIGN KEY (ticket_no) REFERENCES tickets(ticket_no)
11、视图bookings.flights_v
航班视图
Column | Type | Description
---------------------------+-------------+--------------------------------------
flight_id | integer | Flight ID
flight_no | char(6) | Flight number
scheduled_departure | timestamptz | Scheduled departure time
scheduled_departure_local | timestamp | Scheduled departure time,
| | local time at the point of departure
scheduled_arrival | timestamptz | Scheduled arrival time
scheduled_arrival_local | timestamp | Scheduled arrival time,
| | local time at the point of destination
scheduled_duration | interval | Scheduled flight duration
departure_airport | char(3) | Departure airport code
departure_airport_name | text | Departure airport name
departure_city | text | City of departure
arrival_airport | char(3) | Arrival airport code
arrival_airport_name | text | Arrival airport name
arrival_city | text | City of arrival
status | varchar(20) | Flight status
aircraft_code | char(3) | Aircraft code, IATA
actual_departure | timestamptz | Actual departure time
actual_departure_local | timestamp | Actual departure time,
| | local time at the point of departure
actual_arrival | timestamptz | Actual arrival time
actual_arrival_local | timestamp | Actual arrival time,
| | local time at the point of destination
actual_duration | interval | Actual flight duration
12、视图bookings.routes
航班路由信息
Column | Type | Description
------------------------+-----------+-------------------------------------
flight_no | char(6) | Flight number
departure_airport | char(3) | Departure airport code
departure_airport_name | text | Departure airport name
departure_city | text | City of departure
arrival_airport | char(3) | Arrival airport code
arrival_airport_name | text | Arrival airport name
arrival_city | text | City of arrival
aircraft_code | char(3) | Aircraft code, IATA
duration | interval | Flight duration
days_of_week | integer[] | Days of the week on which flights are performed
13、函数bookings.now
回退到数据集的快照时间函数。
14、含bookings.lang
显示语言。
使用
1、修改参数，适配测试样本。（注释语言、now函数回溯快照（倒推到数据集的时间节点））
ALTER DATABASE demo SET bookings.lang = en;
alter role all set search_path=bookings, public;
2、查询（略），详见参考链接
3、购票
BEGIN;
INSERT INTO bookings (book_ref, book_date, total_amount)
VALUES ('_QWE12', bookings.now(), 0);
INSERT INTO tickets (ticket_no, book_ref, passenger_id, passenger_name)
VALUES ('_000000000001', '_QWE12', '1749 051790', 'ALEKSANDR RADISHCHEV');
INSERT INTO ticket_flights (ticket_no, flight_id, fare_conditions, amount)
VALUES ('_000000000001', 8525, 'Business', 0),
('_000000000001', 4967, 'Business', 0);
COMMIT;
…略
参考
https://postgrespro.com/docs/postgrespro/10/demodb-bookings.html