Category: node Mongodb

Node & MongoDB – Drop Collection ”; Previous Next 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. Print Page Previous Next Advertisements ”;

Node & MongoDB Tutorial PDF Version Quick Guide Resources Job Search Discussion Node based application can connect to MongoDB using Node MongoDB Driver. Node MongoDB Driver works with Node on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. Audience This tutorial is designed for Node programmers who would like to understand the MongoDB driver to connect to MongoDB in detail along with its architecture and actual usage. Prerequisites Before proceeding with this tutorial, you should have a good understanding of NodeJS. As you are going to deal with MongoDB database, you should have prior exposure to NoSQL and Database concepts. Print Page Previous Next Advertisements ”;

Node & MongoDB – Display Collections ”; Previous Next 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 Print Page Previous Next Advertisements ”;

Node & MongoDB – Overview ”; Previous Next 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 official documentation is as follows − Node.js is a platform built on Chrome”s JavaScript runtime 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 + [email protected] 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. Print Page Previous Next Advertisements ”;

Node & MongoDB – Delete Documents ”; Previous Next 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. Print Page Previous Next Advertisements ”;

Node & MongoDB – Environment Setup ”; Previous Next Install MongoDB database Follow the MongoDB installation steps using MongoDB – Environment 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) − Live Demo /* 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 Node.js Downloads. At the time of writing this tutorial, following are the versions available on different OS. OS Archive name Windows node-v12.16.1-x64.msi Linux node-v12.16.1-linux-x86.tar.gz Mac node-v12.16.1-darwin-x86.tar.gz SunOS node-v12.16.1-sunos-x86.tar.gz 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. OS Output Linux export PATH=$PATH:/usr/local/nodejs/bin Mac export PATH=$PATH:/usr/local/nodejs/bin FreeBSD export PATH=$PATH:/usr/local/nodejs/bin 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 + [email protected] added 1 package from 1 contributor in 1.781s Print Page Previous Next Advertisements ”;

Node & MongoDB – Show Databases ”; Previous Next 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 } Print Page Previous Next Advertisements ”;

Node & MongoDB – Limit Records ”; Previous Next 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: ”[email protected]”, phone: ”9000012345” }, { _id: 60c4bbb40f8c3920a0e30fde, First_Name: ”Rachel”, Last_Name: ”Christopher”, Date_Of_Birth: ”1990-02-16”, e_mail: ”[email protected]”, phone: ”9000054321” } ] Print Page Previous Next Advertisements ”;

Node & MongoDB – Update Documents ”; Previous Next 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: ”[email protected]” } }, 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. Print Page Previous Next Advertisements ”;