Access Mongo DB through Node JS

We have created Mongo Database through Mongo coding. Even we can access the Mongo DB through Node JS; a Server Side language used in Java Script format.

Node.js can use this module to manipulate MongoDB databases:
var mongo = require('mongodb');

Creating a Database

To create a database in MongoDB, start by creating a MongoClient object, then specify a connection URL with the correct ip address and the name of the database you want to create.

MongoDB will create the database if it does not exist, and make a connection to it.
Example:
Create a database called "mydb":

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
console.log("Database created!");
db.close();
});

Save the code above in a file called "demo_create_mongo_db.js" and run the file:
Run "demo_create_mongo_db.js"

node demo_create_mongo_db.js

Which will give you this result:
Database created!


Create a collection called "customers":

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
db.createCollection("customers", function(err, res) {
if (err) throw err;
console.log("Collection created!");
db.close();
});
});

Save the code above in a file called "demo_mongodb_createcollection.js" and run the file:

Run "demo_mongodb_createcollection.js"
node demo_mongodb_createcollection.js

Which will give you this result:
Collection created!

Insert a document in the "customers" collection:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var myobj = { name: "Company Inc", address: "Highway 37" };
db.collection("customers").insertOne(myobj, function(err, res) {
if (err) throw err;
console.log("1 document inserted");
db.close();
});
});

Save the code above in a file called "demo_mongodb_insert.js" and run the file:

Run "demo_mongodb_insert.js"
node demo_mongodb_insert.js

Which will give you this result:

1 document inserted

Insert multiple documents in the "customers" collection:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;

var myobj = [
{ name: 'John', address: 'Highway 71'},
{ name: 'Peter', address: 'Lowstreet 4'},
{ name: 'Amy', address: 'Apple st 652'},
{ name: 'Hannah', address: 'Mountain 21'},
{ name: 'Michael', address: 'Valley 345'},
{ name: 'Sandy', address: 'Ocean blvd 2'},
{ name: 'Betty', address: 'Green Grass 1'},
{ name: 'Richard', address: 'Sky st 331'},
{ name: 'Susan', address: 'One way 98'},
{ name: 'Vicky', address: 'Yellow Garden 2'},
{ name: 'Ben', address: 'Park Lane 38'},
{ name: 'William', address: 'Central st 954'},
{ name: 'Chuck', address: 'Main Road 989'},
{ name: 'Viola', address: 'Sideway 1633'}
];

db.collection("customers").insertMany(myobj, function(err, res) {
if (err) throw err;
console.log("Number of documents inserted: " + res.insertedCount);
db.close();
});
});

Save the code above in a file called "demo_mongodb_insert_multiple.js" and run the file:

Run "demo_mongodb_insert_multiple.js"
node demo_mongodb_insert_multiple.js

Which will give you this result:

Number of documents inserted: 14
Find the first document in the customers collection:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
db.collection("customers").findOne({}, function(err, result) {
if (err) throw err;
console.log(result.name);
db.close();
});
});

Save the code above in a file called "demo_mongodb_findone.js" and run the file:

Run "demo_mongodb_findone.js"
node demo_mongodb_findone.js

Which will give you this result:

Company Inc.

Find all documents in the customers collection:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
db.collection("customers").find({}).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});

Save the code above in a file called "demo_mongodb_find.js" and run the file:

Run "demo_mongodb_find.js"
node demo_mongodb_find.js

Which will give you this result:

[
{ _id: 58fdbf5c0ef8a50b4cdd9a84 , name: 'John', address: 'Highway 71'},
{ _id: 58fdbf5c0ef8a50b4cdd9a85 , name: 'Peter', address: 'Lowstreet 4'},
{ _id: 58fdbf5c0ef8a50b4cdd9a86 , name: 'Amy', address: 'Apple st 652'},
{ _id: 58fdbf5c0ef8a50b4cdd9a87 , name: 'Hannah', address: 'Mountain 21'}
]

Find documents where the address starts with the letter "S":

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var query = { address: /^S/ };
db.collection("customers").find(query).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});

Save the code above in a file called "demo_mongodb_query_s.js" and run the file:

Run "demo_mongodb_query_s.js"
node demo_mongodb_query_s.js

Which will give you this result:

[
{ _id: 58fdbf5c0ef8a50b4cdd9a8b , name: 'Richard', address: 'Sky st 331' },
{ _id: 58fdbf5c0ef8a50b4cdd9a91 , name: 'Viola', address: 'Sideway 1633' }
]