Mongodb Tutorial | MongoDB with NoSQL

Mongo DB
No SQL
SQL to NoSQL
Advantages
Commands
Use Cases

What is MongoDB?

Mongo DB is an source available, document-oriented database based on No SQL for modern web applications and cloud based servers. MongoDB is used to build high volume, scalable and performance databases

A document-based or document-oriented database like Mongo DB use JSON like key-value pairs to store data. Mongo DB use collections instead of tables. Each database contains collections ( table in RDBMS ) which contains documents ( columns in RDBMS ). The number of documents in each documents can be different from others.

How Mongodb Stores data in JSON


    {
        "_id":"5eab0997f687e3ea1b1ea997",
        "name":"user",
        "id":"212",
        "age":"22",
        "address":{
                "city":"new delhi",
                "pin":"110001" 
               }
    }

In above example, MongoDB is using one document, i.e.{} to store all data, but for the same query, RDBMS will create two tables, one for user and another for address.

NoSQL

NoSQL ( Not only SQL ) is query language used to create both relational and non-relational databases, like MongoDB, CouchDB, Redis, Oracle NoSQL. Some blogs describe NoSQL as Non SQL, but actually NoSQL is Not Only SQL.

Some people also says that NoSQL cannot store relationship data. But this term is wrong. Actually NoSQL stores relationship data but can also store non-relational data. This means, NoSQL supports both structured and unstructured data.

NoSQL databases were developed in 2000. NoSQL focus on scalability, performance and simplicity.

NoSQl Vs SQL

NoSQL Vs SQL
	SQL	NoSQL
Type	Relational	Non Relational
Schemas	Pre Defined	Dynamic
Base	Table	key-value, document, graph
Scalability	Vertical	Horizontal
ACID Support	Yes	No ( except Mongo DB)
Joins	Required	Not Compulsory
Data to Object Mapping	Requires ORM i.e. (object-relational mapping)	Not Required in MongoDB

SQL to NoSQL

MongoDB was developed in 2000. JavaScript Developers will learn MongoDB very easily as MongoDB is JSON based. But RDBMS developer might find MongoDB a bit different then traditional databases (SQL based).

Here is a cheatsheet for SQL to NoSQL.

SQL to NoSQL Cheatsheet
SQL	MongoDB
Database	Database
Table	Collection
Row	Document
Column	Field
Index	Index
Joins	$lookup
SELECT * from tablename	db.collections.find()
SELECT * from tablename LIMIT 1	db.collections.findOne()
CREATE TABLE employee ( name VARCHAR(20))	db.createCollection('employee')
INSERT INTO employee VALUES ( avinash)	db.employees.insert({name:'avinash'})

MongoDB advantages

The Advantage of MongoDB over RDBMS is that Mongodb is document based, schema less, fast and scalable.

MongoDB is document database. Each collection can have as many documents to store data.
Schema less database. No need to define length and datatype.
Scalable very easy to scale.
Document Oriented database that stores data in JSON or BSON
Joins support, but not compulsory.
Powerful Query language.
Full ACID transactions.
Both Cloud and on-premises support.

MongoDB Commands in Mongo shell

MongoDB Commands in Mongo shell
Command	Use
mongod	command to start mongodb server
mongo	open db in terminal
mongosh	latest shell for Mongodb 6 and above
show dbs	show all available Databases
use mydb	select mydb Database. If mydb does not exists, it will create mydb
show collections	show all collections in database selected
db	check current database
db.mydb.help()	show all methods used with database
db.dropDatabase()	to drop or delete existing database

Where to use MongoDB

Here are the primary areas where MongoDB is preferred.

Big Data
Content Delivery Management
Unstructured Data
Real Time Analytics
IoT
Mobile Apps
Web Applications

Companies Using MongoDB

Here is a list of popular companies using MongoDB Databases in their applications.

Facebook
Google
Adobe
Forbes
Toyota
Ebay
SAP
Electronics Arts
GOV.UK
GE HealthCare