mongodb

What is mongodb?

The mongodb npm package is the official Node.js driver for MongoDB. It provides a high-level API to connect to and interact with MongoDB databases. With this package, developers can perform CRUD operations, manage database connections, and work with MongoDB features like transactions, indexes, and aggregation.

What are mongodb's main functionalities?

Connecting to a MongoDB database

This code sample demonstrates how to connect to a MongoDB database using the MongoClient object provided by the mongodb package.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
async function connect() {
  try {
    await client.connect();
    console.log('Connected to MongoDB');
  } catch (e) {
    console.error(e);
  }
}
connect();

CRUD Operations

This code sample shows how to perform CRUD (Create, Read, Update, Delete) operations on a MongoDB collection using the mongodb package.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function crudOperations() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Create a document
    await collection.insertOne({ a: 1 });

    // Read documents
    const docs = await collection.find({}).toArray();

    // Update a document
    await collection.updateOne({ a: 1 }, { $set: { b: 1 } });

    // Delete a document
    await collection.deleteOne({ b: 1 });
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
crudOperations();

Index Management

This code sample illustrates how to manage indexes in a MongoDB collection, including creating an index and listing all indexes.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function manageIndexes() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Create an index
    await collection.createIndex({ a: 1 });

    // List indexes
    const indexes = await collection.indexes();
    console.log(indexes);
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
manageIndexes();

Aggregation

This code sample demonstrates how to use the aggregation framework provided by MongoDB to process data and compute aggregated results.

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);
const dbName = 'myDatabase';
async function aggregateData() {
  try {
    await client.connect();
    const db = client.db(dbName);
    const collection = db.collection('documents');

    // Perform an aggregation query
    const aggregation = await collection.aggregate([
      { $match: { a: 1 } },
      { $group: { _id: '$b', total: { $sum: 1 } } }
    ]).toArray();
    console.log(aggregation);
  } catch (e) {
    console.error(e);
  } finally {
    await client.close();
  }
}
aggregateData();

Other packages similar to mongodb

mongoose

Mongoose is an Object Data Modeling (ODM) library for MongoDB and Node.js. It manages relationships between data, provides schema validation, and is used to translate between objects in code and the representation of those objects in MongoDB. Mongoose offers a more structured approach to data handling with predefined schemas compared to the flexibility of the mongodb package.

couchbase

Couchbase is the official Node.js client library for the Couchbase database. While Couchbase is a different NoSQL database system with its own set of features and capabilities, the couchbase npm package offers similar functionalities in terms of CRUD operations, connection management, and querying as the mongodb package does for MongoDB.

redis

Redis is an in-memory data structure store, used as a database, cache, and message broker. The npm package for Redis provides Node.js bindings to the Redis server. It is similar to mongodb in that it allows for data storage and retrieval, but it operates in-memory and is typically used for different use cases such as caching.

README

Description

The official MongoDB driver for Node.js. Provides a high-level API on top of mongodb-core that is meant for end users.

MongoDB Node.JS Driver

what	where
documentation	http://mongodb.github.io/node-mongodb-native/
api-doc	http://mongodb.github.io/node-mongodb-native/2.2/api/
source	https://github.com/mongodb/node-mongodb-native
mongodb	http://www.mongodb.org/

Blogs of Engineers involved in the driver

• Christian Kvalheim @christkv http://christiankvalheim.com

Bugs / Feature Requests

Think you’ve found a bug? Want to see a new feature in node-mongodb-native? Please open a case in our issue management tool, JIRA:

• Create an account and login https://jira.mongodb.org.
• Navigate to the NODE project https://jira.mongodb.org/browse/NODE.
• Click Create Issue - Please provide as much information as possible about the issue type and how to reproduce it.

Bug reports in JIRA for all driver projects (i.e. NODE, PYTHON, CSHARP, JAVA) and the Core Server (i.e. SERVER) project are public.

Questions and Bug Reports

• mailing list: https://groups.google.com/forum/#!forum/node-mongodb-native
• jira: http://jira.mongodb.org/

Change Log

http://jira.mongodb.org/browse/NODE

Installation

The recommended way to get started using the Node.js 2.0 driver is by using the NPM (Node Package Manager) to install the dependency in your project.

MongoDB Driver

Given that you have created your own project using npm init we install the mongodb driver and it's dependencies by executing the following NPM command.

npm install mongodb --save

This will download the MongoDB driver and add a dependency entry in your package.json file.

Troubleshooting

The MongoDB driver depends on several other packages. These are.

• mongodb-core
• bson
• kerberos
• node-gyp

The kerberos package is a C++ extension that requires a build environment to be installed on your system. You must be able to build node.js itself to be able to compile and install the kerberos module. Furthermore the kerberos module requires the MIT Kerberos package to correctly compile on UNIX operating systems. Consult your UNIX operation system package manager what libraries to install.

{{% note class="important" %}} Windows already contains the SSPI API used for Kerberos authentication. However you will need to install a full compiler tool chain using visual studio C++ to correctly install the kerberos extension. {{% /note %}}

Diagnosing on UNIX

If you don’t have the build essentials it won’t build. In the case of linux you will need gcc and g++, node.js with all the headers and python. The easiest way to figure out what’s missing is by trying to build the kerberos project. You can do this by performing the following steps.

git clone https://github.com/christkv/kerberos.git
cd kerberos
npm install

If all the steps complete you have the right toolchain installed. If you get node-gyp not found you need to install it globally by doing.

npm install -g node-gyp

If correctly compiles and runs the tests you are golden. We can now try to install the mongod driver by performing the following command.

cd yourproject
npm install mongodb --save

If it still fails the next step is to examine the npm log. Rerun the command but in this case in verbose mode.

npm --loglevel verbose install mongodb

This will print out all the steps npm is performing while trying to install the module.

Diagnosing on Windows

A known compiler tool chain known to work for compiling kerberos on windows is the following.

• Visual Studio c++ 2010 (do not use higher versions)
• Windows 7 64bit SDK
• Python 2.7 or higher

Open visual studio command prompt. Ensure node.exe is in your path and install node-gyp.

npm install -g node-gyp

Next you will have to build the project manually to test it. Use any tool you use with git and grab the repo.

git clone https://github.com/christkv/kerberos.git
cd kerberos
npm install
node-gyp rebuild

This should rebuild the driver successfully if you have everything set up correctly.

Other possible issues

Your python installation might be hosed making gyp break. I always recommend that you test your deployment environment first by trying to build node itself on the server in question as this should unearth any issues with broken packages (and there are a lot of broken packages out there).

Another thing is to ensure your user has write permission to wherever the node modules are being installed.

QuickStart

The quick start guide will show you how to setup a simple application using node.js and MongoDB. Its scope is only how to set up the driver and perform the simple crud operations. For more in depth coverage we encourage reading the tutorials.

Create the package.json file

Let's create a directory where our application will live. In our case we will put this under our projects directory.

mkdir myproject
cd myproject

Enter the following command and answer the questions to create the initial structure for your new project

npm init

Next we need to edit the generated package.json file to add the dependency for the MongoDB driver. The package.json file below is just an example and your will look different depending on how you answered the questions after entering npm init

{
  "name": "myproject",
  "version": "1.0.0",
  "description": "My first project",
  "main": "index.js",
  "repository": {
    "type": "git",
    "url": "git://github.com/christkv/myfirstproject.git"
  },
  "dependencies": {
    "mongodb": "~2.0"
  },
  "author": "Christian Kvalheim",
  "license": "Apache 2.0",
  "bugs": {
    "url": "https://github.com/christkv/myfirstproject/issues"
  },
  "homepage": "https://github.com/christkv/myfirstproject"
}

Save the file and return to the shell or command prompt and use NPM to install all the dependencies.

npm install

You should see NPM download a lot of files. Once it's done you'll find all the downloaded packages under the node_modules directory.

Booting up a MongoDB Server

Let's boot up a MongoDB server instance. Download the right MongoDB version from MongoDB, open a new shell or command line and ensure the mongod command is in the shell or command line path. Now let's create a database directory (in our case under /data).

mongod --dbpath=/data --port 27017

You should see the mongod process start up and print some status information.

Connecting to MongoDB

Let's create a new app.js file that we will use to show the basic CRUD operations using the MongoDB driver.

First let's add code to connect to the server and the database myproject.

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  db.close();
});

Given that you booted up the mongod process earlier the application should connect successfully and print Connected correctly to server to the console.

Let's Add some code to show the different CRUD operations available.

Inserting a Document

Let's create a function that will insert some documents for us.

var insertDocuments = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('documents');
  // Insert some documents
  collection.insertMany([
    {a : 1}, {a : 2}, {a : 3}
  ], function(err, result) {
    assert.equal(err, null);
    assert.equal(3, result.result.n);
    assert.equal(3, result.ops.length);
    console.log("Inserted 3 documents into the document collection");
    callback(result);
  });
}

The insert command will return a results object that contains several fields that might be useful.

• result Contains the result document from MongoDB
• ops Contains the documents inserted with added _id fields
• connection Contains the connection used to perform the insert

Let's add call the insertDocuments command to the MongoClient.connect method callback.

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  insertDocuments(db, function() {
    db.close();
  });
});

We can now run the update app.js file.

node app.js

You should see the following output after running the app.js file.

Connected correctly to server
Inserted 3 documents into the document collection

Updating a document

Let's look at how to do a simple document update by adding a new field b to the document that has the field a set to 2.

var updateDocument = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('documents');
  // Update document where a is 2, set b equal to 1
  collection.updateOne({ a : 2 }
    , { $set: { b : 1 } }, function(err, result) {
    assert.equal(err, null);
    assert.equal(1, result.result.n);
    console.log("Updated the document with the field a equal to 2");
    callback(result);
  });  
}

The method will update the first document where the field a is equal to 2 by adding a new field b to the document set to 1. Let's update the callback function from MongoClient.connect to include the update method.

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  insertDocuments(db, function() {
    updateDocument(db, function() {
      db.close();
    });
  });
});

Delete a document

Next lets delete the document where the field a equals to 3.

var deleteDocument = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('documents');
  // Delete document where a is 3
  collection.deleteOne({ a : 3 }, function(err, result) {
    assert.equal(err, null);
    assert.equal(1, result.result.n);
    console.log("Removed the document with the field a equal to 3");
    callback(result);
  });
}

This will delete the first document where the field a equals to 3. Let's add the method to the MongoClient .connect callback function.

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  insertDocuments(db, function() {
    updateDocument(db, function() {
      deleteDocument(db, function() {
        db.close();
      });
    });
  });
});

Finally let's retrieve all the documents using a simple find.

Find All Documents

We will finish up the Quickstart CRUD methods by performing a simple query that returns all the documents matching the query.

var findDocuments = function(db, callback) {
  // Get the documents collection
  var collection = db.collection('documents');
  // Find some documents
  collection.find({}).toArray(function(err, docs) {
    assert.equal(err, null);
    assert.equal(2, docs.length);
    console.log("Found the following records");
    console.dir(docs);
    callback(docs);
  });
}

This query will return all the documents in the documents collection. Since we deleted a document the total documents returned is 2. Finally let's add the findDocument method to the MongoClient.connect callback.

var MongoClient = require('mongodb').MongoClient
  , assert = require('assert');

// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
  assert.equal(null, err);
  console.log("Connected correctly to server");

  insertDocuments(db, function() {
    updateDocument(db, function() {
      deleteDocument(db, function() {
        findDocuments(db, function() {
          db.close();
        });
      });
    });
  });
});

This concludes the QuickStart of connecting and performing some Basic operations using the MongoDB Node.js driver. For more detailed information you can look at the tutorials covering more specific topics of interest.

Next Steps

• MongoDB Documentation
• Read about Schemas
• Star us on GitHub