Implement MongoDB CRUD Operations

Week-05/Day_04/README.md

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+# MongoDB CRUD Operations
+
+## Introduction
+
+The performing **CRUD** (Create, Read, Update, Delete) operations in MongoDB. This is the heart of any database-driven application.
+---
+
+## Create (Insert Data)
+
+Insert a single document:
+
+```js
+db.students.insertOne({
+  name: "Rupesh",
+  age: 23,
+  course: "MCA"
+});
+```
+
+Insert multiple documents:
+
+```js
+db.students.insertMany([
+  { name: "Amit", age: 22 },
+  { name: "Sneha", age: 21 }
+]);
+```
+
+---
+
+## Read (Fetch Data)
+
+Get all documents:
+
+```js
+db.students.find();
+```
+
+Get specific data:
+
+```js
+db.students.find({ name: "Rupesh" });
+```
+
+Pretty format:
+
+```js
+db.students.find().pretty();
+```
+
+---
+
+## Update Data
+
+Update one document:
+
+```js
+db.students.updateOne(
+  { name: "Rupesh" },
+  { $set: { age: 24 } }
+);
+```
+
+Update multiple:
+
+```js
+db.students.updateMany(
+  { course: "MCA" },
+  { $set: { status: "active" } }
+);
+```
+
+---
+
+## Delete Data
+
+Delete one document:
+
+```js
+db.students.deleteOne({ name: "Rupesh" });
+```
+
+Delete many:
+
+```js
+db.students.deleteMany({ age: { $lt: 23 } });
+```
+
+---
+
+## Query Operators
+
+```js
+db.students.find({ age: { $gt: 20 } });
+```
+
+Operators:
+
+* `$gt` → greater than
+* `$lt` → less than
+* `$eq` → equal
+
+---
+
+## Indexing (Basic)
+
+```js
+db.students.createIndex({ name: 1 });
+```
+
+Improves query performance.