Node JS

CRUD Operations
Crud stands for Create Read Update and delete operations. According to the definition crud operation means the way to create an object then read the object then update that if needed a finally delete all data after use. Crud operation is used to make those changes to storage systems.
JWT
JWT The JSON web tokens are known as secure identification for websites which helps to make sure that the requests getting from the user side are originally from a valid user or not. Jwt is basically a json object that holds user information and matches with the information that the user provides on the website.
For an example

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
Is a token when we decode the token we get
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022
}

The object that holds information
Mongoose
Mongoose is a node-based library for MongoDB. The main objective of mongoose is to provide developers to enforce a specific schema at the application.
Relational database (MySql)
My Sql is a popular database system for storing data. All the datas are stored is a table row everytime in my sql database.My sql uses structure query language (SQL).in MySQL one can access associated data using joins which minimizes duplication.
Where mongo DB or any othe no sql databases stores data in json formate but my sql stores data on table raw basis.
NODE js
Node js is an asynchronous backend related javascript run time. Node js is used to create scalable live application.Node.js takes the event model a bit further. It presents an event loop as a runtime construct instead of as a library. In other systems, there is always a blocking call to start the event loop.