/mongodb

better than sql

Primary LanguagePython

Structure

  • NoSQL
  • Non-relational
  • Uses embedded documents instead of joins
  • Automatically creates db/collection if it doesn't exist already

How to Install

  1. Follow the MongoDB link
  2. choose your OS
  3. Select the latest version
  4. Click 'Download'
  5. Follow the steps in the set up wizard
    • make sure "Install MongoDB Compass" is checked

MongoDB Shell

Install
$ sudo apt install mongodb
Launch Mongo Shell

Using the default host and port

  • {host} => custom host
  • {port} => custom port
$ mongo

Using a custom host and port

$ mongo {host}:{port}

Connect Remote:

  • {username} => your mongoDB username
  • {server} => your mongoDB cluster
$ mongo "mongodb+srv://{server}/{dbname}" --username {username}
Finding and Selecting Databases and Collections

Show all databases

> show dbs

select a database

  • {database} => database you want to use
> use {database}
Basic Operations
  • {collection} => the collection you want to use
  • to specify a criteria, use JSON notation
  • {} => refers to all documents
> db.{collection}.find({}) # find all documents
> db.{collection}.find({"CS industry":"data science"}) # find all documents with the given criteria

> db.{collection}.insertOne({"game":"fortnite"}) # insert 1 element
> db.{collection}.insertMany([{"game":"fortnite"}, {"game":"angry birds"}]) # insert multiple elements (NEEDS TO BE AN ARRAY)

> db.{collection}.deleteOne({"language":"sql"}) # delete the first element with a matching criteria
> db.{collection}.deleteMany({"subject":"research"}) # delete all elements with a matching criteria
> db.{collection}.deleteMany({}) # clears all the documents in the db

# 1st argument: criteria
# 2nd argument: update to
# updateOne(<CRITERIA>, {$set:<NEW ENTRY>})
> db.{collection}.updateOne({"name":"omruti"}, {$set:{"loves":"fortnite"}}) # update one