MongoDB basic tutorial

MongoDB is a database, which is the part of the application that is responsible for storing and retrieving information.

MongoDB is a NoSQL database. underNoSQLWe put all databases that do not use SQL language in the query data.

Main features of MongoDB

MongoDB is a very friendly JavaScript database. It exposes a JavaScript API that can be used to create databases and collections of objects (calledDocuments).

it isModeless, Which means you don’t need to pre-define a structure for the data before storing it.

In MongoDB, you can store any object without worrying about the specific fields that make up the object and how to store them. You tell MongoDB to store the object.

Data is stored in a format similar to JSON, but after enhancements, it can store more than just basic data types.


Let's proceed to install MongoDB. You can use one of the many cloud providers that provide access to MongoDB instances, but for the sake of learning, we will install it ourselves.

I am using a Mac, so the installation instructions in this tutorial refer to that operating system.

Open the terminal and run:

brew tap mongodb/brew
brew install mongodb-community

That's it.

Assuming you know how to use the terminal andHow to install homebrew software.

The installation process tells us:

To have launchd start mongodb now and restart at login:
  brew services start mongodb-community
Or, if you don't want/need a background service you can just run:
  mongod --config /usr/local/etc/mongod.conf

You can choose to either launch MongoDB once and have it running forever as a background service in your computer (the thing I prefer), or you can run it just when you need it, by running the latter command.

The default configuration for MongoDB is this:

  destination: file
  path: /usr/local/var/log/mongodb/mongo.log
  logAppend: true
  dbPath: /usr/local/var/mongodb

Logs are stored in /usr/local/var/log/mongodb/mongo.log and the database is stored in /usr/local/var/mongodb.

By default there is no access control, anyone can read and write to the database.

The Mongo Shell

The best way to experiment with MongoDB and starting to interact with it is by running the mongo program, which starts the MongoDB shell.

You can now enter any command that Mongo understands.

Create a database

When you start, Mongo creates a database called test. Run db in the shell to tell you the name of the active database

To change the database, just write use newname and the newname database will be instantly created and the shell switches to using that.

Use show databases to list the available databases:

As you can see, the something database is not listed, just because there is no collection yet in it. Let’s create one.


In MongoDB, a collection is the equivalent of a SQL database table.

You create a collection on the current database by using the db.createCollection() command. The first argument is the database name, and you can pass an options object as a second parameter.

Once you do so, show databases will list the new database, and show collections will list the collection.

You can also create a new collection by using it as a property of the db object, and calling insert() to add an object to the collection:

db.dogs.insert({ name: 'Roger' })

Listing objects in a collection

To show the objects added to a collection, use the find() method:

As you can see there is an additional _id property for the record we added. That’s automatically generated for us by MongoDB.

Now, add more dogs:

db.dogs.insert({ name: 'Buck' })
db.dogs.insert({ name: 'Togo' })
db.dogs.insert({ name: 'Balto' })

Calling db.dogs.find() will give us all the entries, while we can pass a parameter to filter and retrieve a specific entry, for example with db.dogs.find({name: 'Roger'}):

The find() method returns a cursor you need to iterate on.

There is another method which is handy when you know you’ll only get one record, which is findOne(), and it’s used in the same way. If multiple records match a query, it will just return the first one.

Updating records

To update a record you can use the update() method on a collection:

Removing records

You can remove a record calling the remove() method on a collection, passing an object to help identify it:

To remove all the entries from a collection, pass an empty object:


More database tutorials: