MongoDB Fundamentals - (Basic Commands)

Let's talk about MongoDB - The database for modern applications

MongoDB is a general-purpose, document-based, distributed database built for modern application developers and the cloud era. No database makes you more productive.

Installation

These Links provide instructions to install MongoDB Community Edition for supported Linux systems.
These Links provide instructions to install MongoDB Community Edition for macOS systems.
These Links provide instructions to install MongoDB Community Edition for Windows systems.

Basic MongoDB commands

Open your terminal, command prompt, power shell or bash. Whichever you have installed on your system and let's get started

To start the MongoDB shell,
```
mongo
```
Will create a database named amazon and switch to it
```
use amazon
```
Will show you the current database you're in
```
db
```
Will display all databases you have
```
show dbs
```
Will create a collection called products with documents name and macbook value in the amazon database
```
db.products.insert({name: "macbook"})
```
Will create a collection of users
```
db.createCollection("users")
```
Will show a list of collections in your database
```
show collections
```
Will delete the collection users from the database
```
db.users.drop()
```
Will delete the entire database you are currently on
```
db.dropDatabase()
```

Creates a collection products and inserts one document into it

db.products.insertOne({name: "macbook", price: 1500, category: "Computers"})

Will help us find all the documents in the products collection
```
db.products.find()
```

Will creates many documents into the product collection

db.products.insertMany([{name: "iPhone 11", price: 1900, category: " Electronics"}, {name: "Headphone", price: 120, category: "Electronics" }])

Reading (flittering) query's from MongoDB

The find() helps us find every document in a collection e.g in products below
```
db.products.find()
```
Returns the collection results in JSON format
```
db.products.find().pretty()
```
Finds a specific item passed in, if it exists
```
db.products.find({name: "macbook"})
```
Finds a specific key only
```
db.products.find({}, {name: 1})
```
Finds a specific key only and hide the _id
```
db.products.find({}, {name: 1, _id: 0})
```
Finds a specific key only, hide the _id and show only the first 2
```
db.products.find({}, {name: 1, _id:0}).limit(2)
```

Finds every item that is less than 150

db.products.find({price : {$lt: 150} })

Finds every item that is less than or equal to 150
```
db.products.find({price : {$lte: 150} })
```

Finds every item that is grater than 800

db.products.find({price : {$gt: 800} })

Finds every item that is grater than or equal to 800
```
db.products.find({price : {$gte: 800} })
```
Finds every item that its price is less than 200 and belongs to the category of Electronics
```
db.products.find({$and: [{price: {$lt:200}}, {category: "Electronics"} ]})
```
Finds every item that its price is greater than 500 or belongs to the category of Electronics
```
db.products.find({$or: [{price: {$gt:500}}, {category: "Electronics"} ]})
```