+++ date = "2015-03-17T15:36:56Z" title = "Quick Start" [menu.main] identifier = "Quick Start" weight = 15 pre = "" +++
This guide will show you how to set up 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, see the [tutorials]({{< relref "reference/index.md" >}}).
First, create a directory where your application will live.
mkdir myproject
cd myproject
Enter the following command and answer the questions to create the initial structure for your new project:
npm init
Next, install the driver dependency.
npm install mongodb --save
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.
For complete MongoDB installation instructions, see the manual.
- Download the right MongoDB version from MongoDB
- Create a database directory (in this case under /data).
- Install and start a
mongod
process.
mongod --dbpath=/data
You should see the mongod process start up and print some status information.
Create a new app.js file and add the following code to try out some basic CRUD operations using the MongoDB driver.
Add code to connect to the server and the database myproject:
{{% basic-connection %}}
Run your app from the command line with:
node app.js
The application should print Connected successfully to server to the console.
Add to app.js the following function which uses the insertMany method to add three documents to the documents collection.
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 collection");
callback(result);
});
}
The insert command returns an object with the following fields:
- 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
Add the following code to call the insertDocuments 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 successfully to server");
insertDocuments(db, function() {
db.close();
});
});
Run the updated app.js file:
node app.js
The operation returns the following output:
Connected successfully to server
Inserted 3 documents into the collection
Add a query that returns all the documents.
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);
console.log("Found the following records");
console.log(docs)
callback(docs);
});
}
This query returns all the documents in the documents collection. 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() {
findDocuments(db, function() {
db.close();
});
});
});
Add a query filter to find only documents which meet the query criteria.
var findDocuments = function(db, callback) {
// Get the documents collection
var collection = db.collection('documents');
// Find some documents
collection.find({'a': 3}).toArray(function(err, docs) {
assert.equal(err, null);
console.log("Found the following records");
console.log(docs);
callback(docs);
});
}
Only the documents which match 'a' : 3
should be returned.
The following operation updates a document in the documents collection.
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 updates the first document where the field a is equal to 2 by adding a new field b to the document set to 1. Next, 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 successfully to server");
insertDocuments(db, function() {
updateDocument(db, function() {
db.close();
});
});
});
Remove the document where the field a is equal to 3.
var removeDocument = 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);
});
}
Add the new 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 successfully to server");
insertDocuments(db, function() {
updateDocument(db, function() {
removeDocument(db, function() {
db.close();
});
});
});
});
Indexes can improve your application's performance. The following function creates an index on the a field in the documents collection.
{{% index-collection %}}
Add the indexCollection
method to your app:
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 successfully to server");
insertDocuments(db, function() {
indexCollection(db, function() {
db.close();
});
});
});
For more detailed information, see the [tutorials]({{< relref "tutorials/index.md" >}}).