How to use Mongodb - Chen Li

How to use Mongodb

What is Mongodb

Mongodb is an open-source document oriented database developed by Mongodb.Inc. It is classified as a NoSQL database. It is widely used as document database in microservice projects.

How to install Mongodb

Mongodb has a lot of good tools for us to put our database on cloud. I don’t really know about it. Therefore, I installed mongodb-atlas at first. However, this is not mongodb running on locally. It contains several shell tools and a project called atlas to create a cluster on your mongodb cloud.

If you wanna deploy your database on cloud, you can install mongodb-atlas and setup your mongodb atlas.

brew install mongodb-atlas
atlas setup

If you prefer to run mongodb locally, you should install mongodb-community@6.0 instead. For more comprehensive and detailed information, you can read this guide Install Mongodb Community Edition.

Use Mongodb in shell

It’s very necessary to know how to CRUD in mongodb at first.

We have a database called use sample_mflix in this tutorial. You can use show dbs to show all databases. show collections can list all collections in your selected(used) database.

Create

Insert one record.

use sample_mflix

db.movies.insertOne(
  {
    title: "The Favourite",
    genres: [ "Drama", "History" ],
    runtime: 121,
    rated: "R",
    year: 2018,
    directors: [ "Yorgos Lanthimos" ],
    cast: [ "Olivia Colman", "Emma Stone", "Rachel Weisz" ],
    type: "movie"
  }
)

Insert many records.

use sample_mflix

db.movies.insertMany([
   {
      title: "Jurassic World: Fallen Kingdom",
      genres: [ "Action", "Sci-Fi" ],
      runtime: 130,
      rated: "PG-13",
      year: 2018,
      directors: [ "J. A. Bayona" ],
      cast: [ "Chris Pratt", "Bryce Dallas Howard", "Rafe Spall" ],
      type: "movie"
    },
    {
      title: "Tag",
      genres: [ "Comedy", "Action" ],
      runtime: 105,
      rated: "R",
      year: 2018,
      directors: [ "Jeff Tomsic" ],
      cast: [ "Annabelle Wallis", "Jeremy Renner", "Jon Hamm" ],
      type: "movie"
    }
])

Then we can use db.collection_name.find() method to find records we added before.

Read

Read all records.

db.movies.find()

// select * from movies;

Specify Conditions.

db.movies.find( { "title": "The Favourite" } )

// select * from movies where title='The Favourite';

db.movies.find( { rated: { $in: [ "PG", "PG-13" ] } } )

// select * from movies where rated in ("PG", "PG-13");

// and
db.movies.find( { countries: "Mexico", "imdb.rating": { $gte: 7 } } )

// or
db.movies.find( {
     year: 2010,
     $or: [ { "awards.wins": { $gte: 5 } }, { genres: "Drama" } ]
} )

Update

Update a single record.

db.movies.updateOne( { title: "Tag" },
{
  $set: {
    plot: "One month every year, five highly competitive friends
           hit the ground running for a no-holds-barred game of tag"
  }
  { $currentDate: { lastUpdated: true } }
})

Update several records.

db.listingsAndReviews.updateMany(
  { security_deposit: { $lt: 100 } },
  {
    $set: { security_deposit: 100, minimum_nights: 1 }
  }
)

Replace all content except id.

db.accounts.replaceOne(
  { account_id: 371138 },
  { account_id: 893421, limit: 5000, products: [ "Investment", "Brokerage" ] }
)

Delete

Delete all.

db.movies.deleteMany({})

Delete all match some condition.

db.movies.deleteMany( { title: "Titanic" } )

Delete only one match some condition.

db.movies.deleteOne( { cast: "Brad Pitt" } )