The use case for demo purposes used here is explained as follows. The system we are designing is an e-commerce discount calculation system.

The rules for the discount calculation are –

1. Give the user a discount of 10% over MRP if the following conditions are followed –
   • The user’s country is India.
   • The user’s loyalty factor is less than or equal to 2.
   • All the orders purchased by the user so far should amount to more than 5,000.
   • User should have at least made more than two successful orders.
   • The user should have visited the site more than two times every month.
2. Give the user a discount of 20% over MRP if the following conditions are followed –
   • The user’s country is India.
   • The user’s loyalty factor is equal to 3.
   • All the orders purchased by the user so far should amount to more than 10,000.
   • User should have at least made more than two successful orders.
   • The user should have visited the site more than two times every month.
3. Give the user a discount of 25% over MRP if the following conditions are followed –
   • The user’s country is not India.
   • The user’s loyalty factor is greater than or equal to 2.
   • All the orders purchased by the user so far should amount to more than 10,000.
   • User should have at least made more than two successful orders.
   • The user should have visited the site more than five times every month.
4. Give the user a discount of 30% over MRP if the following conditions are followed –
   • The user’s loyalty factor is greater than 3.
   • All the orders purchased by the user so far should amount to more than 50,000 but less than 100,000.
   • User should have at least made more than five successful orders.
   • The user should have visited the site more than fifteen times every month.
5. Give the user a discount of 30% over MRP if the following conditions are followed –
   • The user’s loyalty factor is greater than 3.
   • All the orders purchased by the user so far should amount to more than 100,000.
   • User should have at least made more than fifteen successful orders.
   • The user should have visited the site more than 25 times every month.
6. Give 0% discount in any other case.

Here the inputs will be of three different types as they are coming from three different data sources/APIs.

This input has information like –

• Name
• Country
• Email
• Credit history
• Loyalty factor
• Sum of the purchases made by the user till date.

This input is a summarization of the orders made by the user so far. This input has information like –

• Total number of orders
• Recurring items in those orders if any

This input is a summarization of the telemetry information collected based on the user’s visit to the site. This input has information like –

• Number of visits to the site per month
• Percentage of the number of times the user purchased something to the number of times the user visited