What is MongoDB

MongoDB is a NoSQL Database. It is an open-source document-oriented database and written in c++. it is used for a high volume of data storage. It is not a relational database. It has important features like indexing, regular expression, sharding data, etc.

Advantages:-

Schemaless

Scalability

Performance

High Availability

etc.

Note:- Datastore in the MongoDB as a key-value format.

Example:-

employees collection

{
	name:"John",
	age:35,
	department:"Department A"

}

Mongo DB works based on collection and Document

Collection:- Collection is a group of MongoDB documents. It is the equivalent of an RDBMS table but it has not enforced to the same structure of the document so it is possible documents have a different structures in the collection.

Document:- it is based on key-value pairs and document the same as a row in RDBMS. Documents have a dynamic schema. Dynamic schema means that documents in the same collection do not need to have the same set of fields or structures.

Example:- employees collection
One Document has this structure

{
	name:"John",
	age:35,
	department:"Department A"

}

The second Document has a different structure

{
	name:"John",
	age:35,
	skill:["NodeJS","Angular","MongoDB","MySQL"],
	department:"Department A",


}

compare RDBMS and Mongo DB structure

RDBMS

MongoDB

Table

Collection

Row

Document

Column

Key