MongoDB (Cross-platform Document-Oriented Database)

MongoDB is a NoSQL database where each record is a document comprising of key-value pairs that are similar to JSON objects with schemas. MongoDB is flexible and allows its users to create schema, databases, tables, etc.

Documents that are identifiable by a primary key make up the basic unit of MongoDB. Once MongoDB is installed, users can make use of Mongo shell as well. Mongo shell provides a JavaScript interface through which the users can interact and carry out CRUD operations. 

In other words we can say that MongoDB is a general purpose, document-based, distributed database built for modern application developers and for the cloud era licensed under the Server Side Public License. 

Why use MongoDB?  

• Scalable and can serve several machines.
• It is JavaScript Based which makes it easier to use.
• Has Faster response because it is a document-oriented database.
• Simpler Environment Setup
• It uses JSON syntax which is very easy to use and has a wide range of browser compatibility.
• Data is stored in the form of JSON whether it is Objects, Object Members, Arrays, Values and Strings.
• Uber and Stack Companies uses MongoDB!

Writing queries in MongoDB

Let’s look at some common queries in MongoDB

• Creating a student database  

 use student; 

• Creating a students table  

 db.createCollection("students"); 

• Inserting records into the students collection 

 db.students.insert 
(
    {
        "id" : 1,
        "Name" : "Harry",
                 "Team": "Geeks For Geeks"
    }
); 

• Reading from the students collection 

 db.students.find({Name : "Harry"}).forEach(printjson); 

The main difference between PostgreSQL and MongoDB is that PostgreSQL is a relational database management system that uses SQL, whereas MongoDB is a non-relational, document-oriented database that stores data in flexible, JSON-like documents.