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Today's Learning Update: Backend Basics

Storing Images in a Database We don’t store the actual image in the database; instead, we store its link while the image is hosted elsewhere. Understanding Collections, Schemas & Databases Collection → Similar to a table in SQL. Schema → Defines the fields stored in a collection (e.g., id, name, email). Database (DB) → A container for all collections. HTTP Methods & Postman POST → Sends data to the database (used for creating records). GET → Fetches data from the database. Postman → A tool to send requests to the backend and check responses. Backend Function Calls When we send a POST/GET request from Postman, it's like calling a function. These functions must be defined in our backend (JS file). The JS file acts as a medium that queries the database to store or retrieve data. Postman is like a frontend where we send and request data. Destructuring & Spread Operator in JavaScript Destructuring const obj = { name: "John Doe", email: "john@example.com" }; const { name, email } = obj; console.log(name); // John Doe console.log(email); // john@example.com Makes it easier to access object properties directly. Spread Operator (...) const arr1 = [1, 2, 3, 4]; const arr2 = [5, 6]; const arr3 = [...arr1, ...arr2]; console.log(arr3); // [1, 2, 3, 4, 5, 6] Combines multiple arrays/objects into one. User Registration & Validations Validations ensure that only correct data enters the database (e.g., email format, age limit). When updating an entry, we need to explicitly enable validation: runValidators: true Timestamps (createdAt, updatedAt) Track when a user registered and when they last updated their profile. Platforms like Instagram use this to filter users based on registration date (e.g., last 7 days, 1 month). Immutable Fields Some fields cannot be changed after creation (e.g., emailID). Must be enforced at the schema level. API-Level Validation API acts as a middleware between Postman (client) and the database (server). API validation checks user data before sending it to the database to: Avoid unnecessary DB calls (reducing cost & improving performance). Enhance user experience by preventing delays.

Apr 2, 2025 - 23:59

Storing Images in a Database

We don’t store the actual image in the database; instead, we store its link while the image is hosted elsewhere.

Understanding Collections, Schemas & Databases

Collection → Similar to a table in SQL.

Schema → Defines the fields stored in a collection (e.g., id, name, email).

Database (DB) → A container for all collections.

HTTP Methods & Postman

POST → Sends data to the database (used for creating records).

GET → Fetches data from the database.

Postman → A tool to send requests to the backend and check responses.

Backend Function Calls

When we send a POST/GET request from Postman, it's like calling a function.

These functions must be defined in our backend (JS file).

The JS file acts as a medium that queries the database to store or retrieve data.

Postman is like a frontend where we send and request data.

Destructuring & Spread Operator in JavaScript
Destructuring
const obj = { name: "John Doe", email: "john@example.com" }; const { name, email } = obj; console.log(name); // John Doe console.log(email); // john@example.com
Makes it easier to access object properties directly.
Spread Operator (...)
const arr1 = [1, 2, 3, 4]; const arr2 = [5, 6]; const arr3 = [...arr1, ...arr2]; console.log(arr3); // [1, 2, 3, 4, 5, 6]
Combines multiple arrays/objects into one.

User Registration & Validations
Validations ensure that only correct data enters the database (e.g., email format, age limit).

When updating an entry, we need to explicitly enable validation:
runValidators: true

Timestamps (createdAt, updatedAt)

Track when a user registered and when they last updated their profile.

Platforms like Instagram use this to filter users based on registration date (e.g., last 7 days, 1 month).

Immutable Fields

Some fields cannot be changed after creation (e.g., emailID).

Must be enforced at the schema level.

API-Level Validation
API acts as a middleware between Postman (client) and the database (server).

API validation checks user data before sending it to the database to:

Avoid unnecessary DB calls (reducing cost & improving performance).

Enhance user experience by preventing delays.