System requirements
Functional:
List functional requirements for the system (Ask interviewer if stuck)...
- the system should be able to list all cities where its cinemas are located
- when user select a city, can list all movies in this city
- when user select a movie, can display all cinemas and shows
- user can choose a show and book tickets
- display seat map of a cinema hall
- user can hold a seat for 5 minutes to pay
Non-Functional:
List non-functional requirements for the system...
- high available
- low latency
Capacity estimation
Estimate the scale of the system you are going to design...
DAU: 1 million
API design
Define what APIs are expected from the system...
searchMovie()
bookShow()
Database design
Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...
City table:
cityID
name
state
zipcode
Cinema table:
cinema id
cityID
totalCinemaHall
name
cinemaHall table:
cinemaHall id
cinema id
name
totalSeats
cinemaSeat table:
cinema seat id
cinemaHall id
seatnumber
type
movie table:
movie id
movie name
movie type
show table:
show id
cinemaHall id
movie id
date
starttime
endtime
show seat table:
show seat id
status
seat price
cinemaSeatID
showiD
booking id
booking table:
booking id
numberOfSeats
timestamp
status
user id
show id
High-level design
You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design...
client: mobile, desktop, web
booking server: manage booking related
movie server: manage movie related
user server: manage user related, sign up, login
Request flows
Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...
client send a search movie request, booking server returns a list of shows available
client send a booking request, booking server booked a list of seats selected
Detailed component design
Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...
active booking service:
show id, [booking id, time]
waitingUserService
show id, [user id, wait start time]
Trade offs/Tech choices
Explain any trade offs you have made and why you made certain tech choices...
Failure scenarios/bottlenecks
Try to discuss as many failure scenarios/bottlenecks as possible.
Future improvements
What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?