Examples

Question 1

Design a Sales ranking system by category

Answer 1

Basic Design

1. User only needs to read, updates/datasource are from another service.
2. 1 API for read directly from DB, 1 service for consume the updates/compute and store the result in to DB.
3. the ‘another service’ we can assume that it is a API(better than a raw DB)

Improvements:

1. Too much DB hits, Too much calculation consider using Cache
2. load balancer/ CDN
3. more servers
4. Database scaling (add more/partitioning)
5. Consider using No SQL

Question 2

Design a recipes website for user-input ingredients

Answer 2

Key extra point:

1. Database data model design
2. How to compute the result from many to many relationship
3. Would using Nosql help reduce the computation time
4. check similar question on CCI - system design question 1 find the documents containing the words

Question 3

Designing a shorting URL

Answer 3

1. Cacheing - what to cache, how to update cache

2. URL hashing/generating

Question 4

Database model design

Answer 4

1. list all entities/tables
2. each Entity/table have a PK (***ID)
3. then add foreign_key(otherID)

Question 5

High level design

Answer 5

Client
Server - Read API/ WriteAPI / ComputationService
DataStore - database / External API / Disk

Question 6

Other aspect needs to consider

Answer 6

Security, Permissions

Question 7

Build a e-retail company from scratch

Answer 7

1. brainstorm main usecase : login, browse, select, pay, order
   Login Service
   Memebership Service
   Inventory Order Processing
2. Physically
   Database (implementation of Interfaces)
   Domain Services (Interfaces of any ports, so can invoke and usem import domain)
   Application(invoke services, ports, import ports, services) Ports(implementation of Interfaces)
   common login membership inventory order

In Application
Result1 r1 = service1.processRequest(request); - usecase input port

service2.handle(r1) outputport.handle(rl) - usecase output port