Node & MongoDB – Overview

What is Node.js?

Node.js is a server-side platform built on Google Chrome”s JavaScript Engine (V8 Engine). Node.js was developed by Ryan Dahl in 2009 and its latest version is v0.10.36. The definition of Node.js as supplied by its is as follows −

Node.js is a platform built on for easily building fast and scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

Node.js is an open source, cross-platform runtime environment for developing server-side and networking applications. Node.js applications are written in JavaScript, and can be run within the Node.js runtime on OS X, Microsoft Windows, and Linux.

Node.js also provides a rich library of various JavaScript modules which simplifies the development of web applications using Node.js to a great extent.

Node.js = Runtime Environment + JavaScript Library

mongodb

mongodb is node.js driver to connect and perform database operations on MongoDB. To install mongodb, run the following npm command.

npm install mongodb
+ mongodb@3.6.9
added 1 package from 1 contributor in 1.781s

Creating/Connecting to Database

Once mongoClient is instantiated, its connect() method can be used to get connection to a database.

// MongoDBClient
const client = new MongoClient(url, { useUnifiedTopology: true });
// make a connection to the database
client.connect(function(error) {
   if (error) throw error;
   console.log("Connected!");
   // create or connect to database
   const db = client.db(database);
   // close the connection
   client.close();
});

In case database is not present then above command will create the same.

In subsequent chapters, we”ll see the various operations on MongoDB using Node.

Node & MongoDB – Environment Setup

Install MongoDB database

Follow the MongoDB installation steps using

Install Node

Live Demo Option Online

You really do not need to set up your own environment to start learning Node.js. Reason is very simple, we already have set up Node.js environment online, so that you can execute all the available examples online and learn through practice. Feel free to modify any example and check the results with different options.

Try the following example using the Live Demo option available at the top right corner of the below sample code box (on our website) −

/* Hello World! program in Node.js */
console.log("Hello World!");

For most of the examples given in this tutorial, you will find a Try it option, so just make use of it and enjoy your learning.

Local Environment Setup

If you are still willing to set up your environment for Node.js, you need the following two softwares available on your computer, (a) Text Editor and (b) The Node.js binary installables.

Text Editor

This will be used to type your program. Examples of few editors include Windows Notepad, OS Edit command, Brief, Epsilon, EMACS, and vim or vi.

Name and version of text editor can vary on different operating systems. For example, Notepad will be used on Windows, and vim or vi can be used on windows as well as Linux or UNIX.

The files you create with your editor are called source files and contain program source code. The source files for Node.js programs are typically named with the extension “.js“.

Before starting your programming, make sure you have one text editor in place and you have enough experience to write a computer program, save it in a file, and finally execute it.

The Node.js Runtime

The source code written in source file is simply javascript. The Node.js interpreter will be used to interpret and execute your javascript code.

Node.js distribution comes as a binary installable for SunOS , Linux, Mac OS X, and Windows operating systems with the 32-bit (386) and 64-bit (amd64) x86 processor architectures.

Following section guides you on how to install Node.js binary distribution on various OS.

Download Node.js archive

Download latest version of Node.js installable archive file from . At the time of writing this tutorial, following are the versions available on different OS.

Installation on UNIX/Linux/Mac OS X, and SunOS

Based on your OS architecture, download and extract the archive node-v12.16.1-osname.tar.gz into /tmp, and then finally move extracted files into /usr/local/nodejs directory. For example:

$ cd /tmp
$ wget http://nodejs.org/dist/v12.16.1/node-v12.16.1-linux-x64.tar.gz
$ tar xvfz node-v12.16.1-linux-x64.tar.gz
$ mkdir -p /usr/local/nodejs
$ mv node-v12.16.1-linux-x64/* /usr/local/nodejs

Add /usr/local/nodejs/bin to the PATH environment variable.

Installation on Windows

Use the MSI file and follow the prompts to install the Node.js. By default, the installer uses the Node.js distribution in C:Program Filesnodejs. The installer should set the C:Program Filesnodejsbin directory in window”s PATH environment variable. Restart any open command prompts for the change to take effect.

Verify installation: Executing a File

Create a js file named main.js on your machine (Windows or Linux) having the following code.

/* Hello, World! program in node.js */
console.log("Hello, World!")

Now execute main.js file using Node.js interpreter to see the result −

$ node main.js

If everything is fine with your installation, this should produce the following result −

Hello, World!

mongodb

mongodb is node.js driver to connect and perform database operations on MongoDB. To install mongodb, run the following npm command.

npm install mongodb
+ mongodb@3.6.9
added 1 package from 1 contributor in 1.781s

Node & MongoDB – Connecting Database

Node mongodb provides mongoClient object which is used to connect a database connection using connect() method. This function takes multiple parameters and provides db object to do database operations.

Syntax

// MongoDBClient
const client = new MongoClient(url, { useUnifiedTopology: true });
// make a connection to the database
client.connect();

You can disconnect from the MongoDB database anytime using another connection object function close().

Syntax

client.close()

Example

Try the following example to connect to a MongoDB server −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!

Node & MongoDB – Show Databases

To show databases, you can use admin.listDatabases() method to get the name of all the databases where admin represents the admin class.

MongoClient.connect(url, function(error, client) {
   // Use the admin database for the operation
   const adminDb = client.db(''myDb'').admin();
   // List all the available databases
   adminDb.listDatabases(function(err, dbs) {
      console.log(dbs);
   });
});

Example

Try the following example to connect to a MongoDB server −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Use the admin database for the operation
   const adminDb = client.db(''myDb'').admin();
   // List all the available databases
   adminDb.listDatabases(function(err, dbs) {
      console.log(dbs);
   });
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
{
  databases: [
    { name: ''admin'', sizeOnDisk: 40960, empty: false },
    { name: ''config'', sizeOnDisk: 36864, empty: false },
    { name: ''local'', sizeOnDisk: 73728, empty: false }
  ],
  totalSize: 151552,
  ok: 1
}

Node & MongoDB – Drop Database

To drop a database, you can use database.drop() method to drop the selected database.

MongoClient.connect(url, function(error, client) {
   // Connect to the database
   const database = client.db(''myDb'');   
   // Drop the database
   database.dropDatabase();
});

Example

Try the following example to drop a mongodb database −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');
   
   // Drop the database
   database.dropDatabase();
   
   console.log("Database dropped!");
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
Database dropped!

Node & MongoDB – Create Collection

To create a collection, you can use database.createCollection() method to create a collection.

MongoClient.connect(url, function(error, client) {
   // Connect to the database
   const database = client.db(''myDb'');   
   // Create the collection
   database.createCollection(''sampleCollection'');
});

Example

Try the following example to create a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');  
   // Create the collection
   database.createCollection(''sampleCollection'');   
   console.log("Collection created.");
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
Collection created.

Node & MongoDB – Drop Collection

To drop a collection, you can use collection.drop() method to drop a collection.

MongoClient.connect(url, function(error, client) {
   // Connect to the database
   const database = client.db(''myDb'');
   // drop the collection
   database.collection(''sampleCollection'').drop(function(error, status) {
      if (error) throw error;
      if (status) {
         console.log("Collection deleted");		  
      }      
   });
});

Example

Try the following example to drop a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');
   // Create the collection
   database.collection(''sampleCollection'').drop(function(error, status) {
      if (error) throw error;
      if (status) {
         console.log("Collection deleted.");		  
      }      
   });
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
Collection deleted.

Node & MongoDB – Display Collections

To display collections of a database, you can use database.listCollections() method to get list of collections.

MongoClient.connect(url, function(error, client) {
   // Connect to the database
   const database = client.db(''myDb'');   
   // get the list of collections
   database.listCollections().toArray(function(err, collections) {
      collections.forEach(collection => console.log(collection.name));
   });
});

Example

Try the following example to create a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');
   // Create the collection
   database.createCollection(''sampleCollection'');   
   database.listCollections().toArray(function(err, collections) {
      collections.forEach(collection => console.log(collection.name));
   });
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
sampleCollection

Node & MongoDB – Insert Document

To insert document(s) in a collection of a database, you can use collection.insertOne() or collection.insertMany() methods to insert one or multiple documents.

database.collection("sampleCollection").insertOne(firstDocument, function(error, res) {
   if (error) throw error;
   console.log("1 document inserted");
});
database.collection("sampleCollection").insertMany(documents, function(error, res) {
   if (error) throw error;
   console.log("Documents inserted: " + res.insertedCount);
});

Example

Try the following example to insert documents in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
const firstDocument = {
   First_Name : ''Mahesh'',
   Last_Name : ''Parashar'',
   Date_Of_Birth: ''1990-08-21'',
   e_mail: ''mahesh_parashar.123@gmail.com'',
   phone: ''9034343345''
};
const documents = [{
   First_Name : ''Radhika'',
   Last_Name : ''Sharma'',
   Date_Of_Birth: ''1995-09-26'',
   e_mail: ''radhika_sharma.123@gmail.com'',
   phone: ''9000012345''
},
{
   First_Name : ''Rachel'',
   Last_Name : ''Christopher'',
   Date_Of_Birth: ''1990-02-16'',
   e_mail: ''rachel_christopher.123@gmail.com'',
   phone: ''9000054321''
},
{
   First_Name : ''Fathima'',
   Last_Name : ''Sheik'',
   Date_Of_Birth: ''1990-02-16'',
   e_mail: ''fathima_sheik.123@gmail.com'',
   phone: ''9000012345''
}
];
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');
   database.collection("sampleCollection").insertOne(firstDocument, function(error, res) {
      if (error) throw error;
      console.log("1 document inserted");
   });
   database.collection("sampleCollection").insertMany(documents, function(error, res) {
      if (error) throw error;
      console.log("Documents inserted: " + res.insertedCount);
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Documents inserted: 3
1 document inserted

Node & MongoDB – Select Documents

To select documents of a collection, you can use collection.findOne() or collection.find() methods to select one or multiple documents.

database.collection("sampleCollection").findOne({}, function(error, result) {
   if (error) throw error;
   console.log(result);
});
database.collection("sampleCollection").find({}).toArray(function(error, result) {
   if (error) throw error;
   console.log(result);
});

Example

Try the following example to select documents in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');      
   database.collection("sampleCollection").findOne({}, function(error, result) {
      if (error) throw error;
      console.log(result);
   });   database.collection("sampleCollection").find({}).toArray(function(error, result) {
      if (error) throw error;
      console.log(result);
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
{
  _id: 60c4bbb40f8c3920a0e30fdd,
  First_Name: ''Radhika'',
  Last_Name: ''Sharma'',
  Date_Of_Birth: ''1995-09-26'',
  e_mail: ''radhika_sharma.123@gmail.com'',
  phone: ''9000012345''
}
[
  {
    _id: 60c4bbb40f8c3920a0e30fdd,
    First_Name: ''Radhika'',
    Last_Name: ''Sharma'',
    Date_Of_Birth: ''1995-09-26'',
    e_mail: ''radhika_sharma.123@gmail.com'',
    phone: ''9000012345''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fde,
    First_Name: ''Rachel'',
    Last_Name: ''Christopher'',
    Date_Of_Birth: ''1990-02-16'',
    e_mail: ''rachel_christopher.123@gmail.com'',
    phone: ''9000054321''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fdf,
    First_Name: ''Fathima'',
    Last_Name: ''Sheik'',
    Date_Of_Birth: ''1990-02-16'',
    e_mail: ''fathima_sheik.123@gmail.com'',
    phone: ''9000012345''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fdc,
    First_Name: ''Mahesh'',
    Last_Name: ''Parashar'',
    Date_Of_Birth: ''1990-08-21'',
    e_mail: ''mahesh_parashar.123@gmail.com'',
    phone: ''9034343345''
  }
]

Node & MongoDB – Update Documents

To update documents of a collection, you can use collection.updateOne() or collection.updateMany() methods to update one or multiple documents.

database.collection("sampleCollection").updateOne(query,updates, function(error, result) {
   if (error) throw error;
   console.log(''Document Updated'');
});
database.collection("sampleCollection").updateMany(query,updates, function(error, result) {
   if (error) throw error;
   console.log(result.result.nModified + " document(s) updated");
});

Example

Try the following example to update a document in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');
   database.collection("sampleCollection").updateOne({First_Name:''Mahesh''},
      { $set: { e_mail: ''maheshparashar@gmail.com'' } }, function(error, result) {
      if (error) throw error;
      console.log(''Document Updated.'');
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
Document Updated.

Node & MongoDB – Delete Documents

To delete documents of a collection, you can use collection.deleteOne() or collection.deleteMany() methods to delete one or multiple documents.

database.collection("sampleCollection").deleteOne(query, function(error, result) {
   if (error) throw error;
   console.log(''Document deleted.'');
});
database.collection("sampleCollection").deleteMany(query, function(error, result) {
   if (error) throw error;
   console.log(result.result.n + " document(s) deleted.");
});

Example

Try the following example to delete a document in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');  database.collection("sampleCollection").deleteOne({First_Name:''Mahesh''}, function(error, result) {
      if (error) throw error;
      console.log(''Document Deleted.'');
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
Document Deleted.

Node & MongoDB – Embedded Document

To insert embedded document(s) in a collection of a database, you can use collection.insertOne() or collection.insertMany() methods to insert one or multiple documents.

database.collection("sampleCollection").insertOne(firstDocument, function(error, res) {
   if (error) throw error;
   console.log("1 document inserted");
});
database.collection("sampleCollection").insertMany(documents, function(error, res) {
   if (error) throw error;
   console.log("Documents inserted: " + res.insertedCount);
});

Example

Try the following example to insert documents in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
const firstPost = {
   title : ''MongoDB Overview'',
   description : ''MongoDB is no SQL database'',
   by: ''tutorials point'',
   url: ''http://www.tutorialspoint.com'',
   comments: [{
      user: ''user1'',
      message: ''My First Comment'',
      dateCreated: ''20/2/2020'',
      like: 0
   },
   {
      user: ''user2'',
      message: ''My Second Comment'',
      dateCreated: ''20/2/2020'',
      like: 0
   }]
};
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''posts'');      
   database.collection("samplePost").insertOne(firstPost, function(error, res) {
   if (error) throw error;
      console.log("1 document inserted");
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected.
1 document inserted

Node & MongoDB – Limit Records

To limit the selected documents of a collection, you can use collection.find().limit() methods to select required documents.

database.collection("sampleCollection").find({}).limit(2).toArray(function(error, result) {
   if (error) throw error;
   console.log(result);
});

Example

Try the following example to select limited documents in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');   database.collection("sampleCollection").find({}).limit(2).toArray(function(error, result) {
      if (error) throw error;
      console.log(result);
   }); 
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
[
  {
    _id: 60c4bbb40f8c3920a0e30fdd,
    First_Name: ''Radhika'',
    Last_Name: ''Sharma'',
    Date_Of_Birth: ''1995-09-26'',
    e_mail: ''radhika_sharma.123@gmail.com'',
    phone: ''9000012345''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fde,
    First_Name: ''Rachel'',
    Last_Name: ''Christopher'',
    Date_Of_Birth: ''1990-02-16'',
    e_mail: ''rachel_christopher.123@gmail.com'',
    phone: ''9000054321''
  }
]

Node & MongoDB – Sorting Records

To sort the selected documents of a collection, you can use collection.find().sort() methods to sort documents.

database.collection("sampleCollection").find({}).sort({First_Name: -1}).toArray(function(error, result) {
   if (error) throw error;
   console.log(result);
});

Example

Try the following example to select limited documents in a mongodb collection −

Copy and paste the following example as mongodb_example.js −

const MongoClient = require(''mongodb'').MongoClient;
// Prepare URL
const url = "mongodb://localhost:27017/";
// make a connection to the database
MongoClient.connect(url, function(error, client) {
   if (error) throw error;
   console.log("Connected!");
   // Connect to the database
   const database = client.db(''myDb'');  
   database.collection("sampleCollection").find({}).sort({First_Name: -1}).toArray(function(error, result) {
      if (error) throw error;
      console.log(result);
   });   
   // close the connection
   client.close();
});

Output

Execute the mysql_example.js script using node and verify the output.

node mongodb_example.js
Connected!
[
  {
    _id: 60c4bbb40f8c3920a0e30fdd,
    First_Name: ''Radhika'',
    Last_Name: ''Sharma'',
    Date_Of_Birth: ''1995-09-26'',
    e_mail: ''radhika_sharma.123@gmail.com'',
    phone: ''9000012345''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fde,
    First_Name: ''Rachel'',
    Last_Name: ''Christopher'',
    Date_Of_Birth: ''1990-02-16'',
    e_mail: ''rachel_christopher.123@gmail.com'',
    phone: ''9000054321''
  },
  {
    _id: 60c4bbb40f8c3920a0e30fdf,
    First_Name: ''Fathima'',
    Last_Name: ''Sheik'',
    Date_Of_Birth: ''1990-02-16'',
    e_mail: ''fathima_sheik.123@gmail.com'',
    phone: ''9000012345''
  }
]