Create | Insert | Update | Find | Drop | Delete | Sort | Query | Limit | LookUp Join Aggregate In NodeJS and MongoDB

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

the database you want to create.

var MongoClient = require('mongodb').MongoClient; var url = "mongodb://127.0.0.1:27017/";

1. Create DataBase In NodeJs | MongoDB

// MongoDB will create the database if

it does not exist, and make a connection to it.

MongoClient.connect(url, function(err, db) { if (err) throw err; console.log("Database created!"); db.close(); });

2. Create Collection In NodeJs | MongoDB

// To create a collection in MongoDB, use the createCollection() method:

MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.createCollection("user", function(err, res) { if (err) throw err; console.log("Collection created!"); db.close(); }); });

3. Insert In NodsJs | MongoDB

/*Insert Into Collection The first parameter of the insertOne() method is an object containing the name(s) and value(s) of each field in the the document you want to insert*/ MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myobj = { name: "Company Inc", address: "Highway 37" }; dbo.collection("customers").insertOne(myobj, function(err, res) { if (err) throw err; console.log("1 document inserted"); db.close(); }); }); /*Insert Multiple Documents

To insert multiple documents into a collection in MongoDB,

we use the insertMany() method. The first parameter of the

insertMany() method is an array of objects,

containing the data you want to insert.*/   MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myobj = [ { name: 'abc', address: 'new 71'}, { name: 'xyz', address: 'lost 4'}, { name: 'jon', address: 'test st 6562'}, ];     dbo.collection("user").insertMany(myobj, function(err, res) { if (err) throw err; console.log("Number of documents inserted: " + res.insertedCount); db.close();     }); });

4. Find In NodeJs | MongoDB

// Full Documentation - https://www.turbo360.co/docs

The first parameter of the findOne() method is a query object. In this example, we use an empty query object, which selects all

documents in a collection MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.collection("customers").findOne({}, function(err, result) { if (err) throw err; console.log(result.name); db.close(); }); }); //The find() method returns all occurrences in the selection. The first parameter of the find() method is a query object. In this example, we use an empty query object, which selects all documents in the collection. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.collection("customers").find({}).toArray(function(err, result) { if (err) throw err; console.log(result); db.close(); }); });

5. Drop Collection In NodeJs | MongoDB

//The drop() method takes a callback function containing the error object and the result parameter which returns true if the collection was dropped successfully, otherwise, it returns false. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.collection("user").drop(function(err, delOK) { if (err) throw err; if (delOK) console.log("Collection deleted"); db.close(); }); }); //The dropCollection() method takes two parameters: the name of the collection and a callback function MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.dropCollection("customers", function(err, delOK) { if (err) throw err; if (delOK) console.log("Collection deleted"); db.close(); }); });

6. Delete In NodeJs | MongoDB

To delete a record, or document as it is called in MongoDB,

we use the deleteOne() method. Note: If the query finds more than one document,

only the first occurrence is deleted. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myquery = { address: 'Mountain 21' }; dbo.collection("customers").deleteOne(myquery, function(err, obj) { if (err) throw err; console.log("1 document deleted"); db.close(); }); }); //To delete more than one document, use the deleteMany() method. Note: Delete all documents were the address starts with the letter "G": MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myquery = { address: /^G/ }; dbo.collection("customers").deleteMany(myquery, function(err, obj) { if (err) throw err; console.log(obj.result.n + " document(s) deleted"); db.close(); }); });

7.  Sort In  NodeJs |  MongoDB

//Use the sort() method to sort the result in ascending or descending
order. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var mysort = { name: 1 }; dbo.collection("customers").find().sort(mysort).toArray(function(err, result) { if (err) throw err; console.log(result); db.close(); }); });

8.  Query In NodeJs | MongoDB

// Full Documentation - https://www.turbo360.co/docs

When finding documents in a collection, you can filter the result

by using a query object. The first argument of the find() method is

a query object and is used to limit the search MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var query = { address: "Park Lane 38" }; dbo.collection("user").find(query).toArray(function(err, result) { if (err) throw err; console.log(result); db.close(); }); }); //To find only the documents where the "address" field starts with the
letter "G", use the regular expression /^G/ MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var query = { address: /^G/ }; dbo.collection("user").find(query).toArray(function(err, result) { if (err) throw err; console.log(result); db.close(); }); });

9. Limit In NodeJs | MongoDB

//The limit() method takes one parameter,

a number defining how many documents to return. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.collection("customers").find().limit(5).toArray(function(err, result) { if (err) throw err; console.log(result); db.close(); }); });

10. Update In NodeJs | MongoDB

//The first parameter of the updateOne() method is a query

object defining which document to update Note: If the query finds more than one record, only the first occurrence is updated. MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myquery = { address: "Valley 345" }; var newvalues = { $set: {name: "Mickey", address: "Canyon 123" } }; dbo.collection("user").updateOne(myquery, newvalues, function(err, res) { if (err) throw err; console.log("1 document updated"); db.close(); }); }); Update Only Specific Fields When using the $set operator, only the specified fields are updated: ... var myquery = { address: "Valley 345" }; var newvalues = { $set: { address: "Canyon 123" } }; dbo.collection("user").updateOne(myquery, newvalues, function(err, res) { ... Update Many Documents To update all documents that meet the criteria of the query,

use the updateMany() method. Note: Update all documents where the name starts with the letter "G": MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); var myquery = { address: /^G/ }; var newvalues = {$set: {name: "Minnie"} }; dbo.collection("user").updateMany(myquery, newvalues, function(err, res) { if (err) throw err; console.log(res.result.nModified + " document(s) updated"); db.close(); }); });

11. Join In NodeJs | MongoDB

Join the matching "userAddress" address to the "user" collection

MongoClient.connect(url, function(err, db) { if (err) throw err; var dbo = db.db("mydb"); dbo.collection('user').aggregate(

[

{ $lookup: { from: 'userAddress', localField: 'address_id', foreignField: '_id', as: 'address' } } ]).toArray(function(err, res) { if (err) throw err; console.log(JSON.stringify(res)); db.close(); });

});

.