The back-end, also called the server side, consists of the server which provides data on request, the application which channels it, and the database which organizes the information.For example, when a customer browses shoes on a website, they are interacting with the front end.
After they select the item they want, put it in the shopping cart, and authorize the purchase, the information is kept inside the database which resides on the server.
A few days later when the client checks on the status of their delivery, the server pulls the relevant information, updates it with tracking data, and presents it through the front-end. Please refer Back-End Database Class 12 Notes for more information.
CBSE Revision Notes 