The MongoJS Cheat Sheet

Introduction

If you’re looking to use a MongoDB database with your web application running on NodeJS you might be looking at which npm libraries which will allow you to easily interact with MongoDB. MongoJS and Mongoose are the two top choices for developers in this scenario. In this article we’ll give a quick cheat sheet of the common commands you’ll use with MongoJS that will quickly get you oriented MongoJS. We’ll show basic commands and a quick briefing on what each command does.

  • Note: To demo we will use a grocery store db grocerydb and a products collection containing grocery products.

Cheat Sheet

Creating

Create a database or switch to a database. ( You should know that the database is not actually created until you create a collection within it )

use grocerydb

Display the database you are currently working with

db

Create a collection and insert a document in it

db.products.insert({name: "Soda", quantity: 300, brand: "DemoBrand", departments: ["Checkout", "Beverages"]})

Finding

Get all the documents in a collection

db.products.find()

Use the .pretty() to make finds more readable

db.products.find().pretty()

Find documents with a matching field

db.products.find({name: "Soda"})

Find documents matching multiple fields

db.products.find({name: "Soda", brand: "DemoBrand"})

Find documents with a matching entry in an array field

db.products.find({departments: {$in: ["Beverages"]}})

Find a document by _id

db.products.find({_id: ObjectId("defe16fe1d94bcf86cd78543defe")})

Updating

Update a document. This example will update the soda entry brand. This will only update the first entry where name = “Soda”. If you want to update multiple documents we will show you how to do that next.

db.products.update({"name": "Soda"}, {$set: {"brand": "newBrand"}})

Update multiple documents

db.products.update({"name": "Soda"}, {$set: {"brand": "newBrand"}}, {multi: true})

Add a value to an array field

db.products.update({"name": "Soda"}, {$push: {"departments": "Clearnace"}})

Deletion

Delete a document

db.products.remove({"name": "Soda"})

Delete all documents in a collection

db.products.remove({})

Drop/Delete a collection

db.products.drop()

Drop/Delete a database

db.dropDatabase()

Conclusion

In this cheat sheet we gave you the basic CRUD ( Create, Read, Update, Delete ) commands that will be used with MongoJS. MongoJS is a very easy library to get up and running with so get started and try out some commands. You can get MongoJS from npm by running npm install mongojs. There are tons of variations and more commands out there for MongoDB but this should serve as a good starting point and reference for anybody using the MongoJS npm library. If you need more help defining a schema for your data, then you might look into the Mongoose library which is great for that scenario. MongoJS provides functions for all MongoDB functionality but you’ll have to manage the schema yourself. It’s more of a low-level library than Mongoose which has it’s advantages and disadvantages depending on your application.

We hope you find this cheat sheet helpful in getting acquainted with MongoJS. If you have any feedback on commands we could add please don’t hesitate to reach out to us.

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