1.What’s MongoDB?

MongoDB is a document database which belongs to a family of databases called NoSQL – not only SQL. In MongoDB, records are documents which behave a lot like JSON objects in JavaScript. Values in documents can be looked up by their field’s key. Documents can have some fields/keys and not others, which makes Mongo extremely flexible.

This is different than SQL databases like MySQL and PostgreSQL, where fields correspond to columns in a table and individual records correspond to rows.

2. Install and Run MongoDB with Homebrew

• Open the Terminal app and type brew update.
• After updating Homebrew brew install mongodb

• The install creates:
  the configuration file (/usr/local/etc/mongod.conf)

  systemLog:
      destination: file
      path: /usr/local/var/log/mongodb/mongo.log
      logAppend: true
  storage:
      dbPath: /usr/local/var/mongodb
  net:
      bindIp: 127.0.0.1
  

  the log directory path (/usr/local/var/log/mongodb)
  the data directory path (/usr/local/var/mongodb)

3. Run the MongoDB daemon

In one of your terminal windows run mongod. This should start the Mongo server.
Oops, something is wrong:

[main] Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'
[initandlisten] MongoDB starting : pid=13410 port=27017 dbpath=/data/db 64-bit host=Zhihuis-Mac-mini.local
[initandlisten] db version v4.0.3
[initandlisten] git version: 7ea530946fa7880364d88c8d8b6026bbc9ffa48c
[initandlisten] allocator: system
[initandlisten] modules: none
[initandlisten] build environment:
[initandlisten]     distarch: x86_64
[initandlisten]     target_arch: x86_64
[initandlisten] options: {}
[initandlisten] exception in initAndListen: NonExistentPath: Data directory /data/db not found., terminating
[initandlisten] shutdown: going to close listening sockets...
[initandlisten] removing socket file: /tmp/mongodb-27017.sock
[initandlisten] now exiting
[initandlisten] shutting down with code:100

It complains that exception in initAndListen: NonExistentPath: Data directory /data/db not found.

You can either

• create the db folder manually by mkdir -p /data/db, Make sure that the /data/db directory has the right permissions by running

  > sudo chown -R `id -un` /data/db
  > # Enter your password
  

  or

• Specify the mongod.conf when Running the daemon mongod --config /usr/local/etc/mongod.conf. The db file locates in /usr/local/var/log/mongodb

Alternatively, to run MongoDB as a macOS service, issue the following (the process uses the /usr/local/etc/mongod.conf file, created during the install):
brew services start mongodb

4. Connect and Use MongoDB

mongo

5. Exit/Stop the Mongo

To exit the Mongo shell run quit()
To stop the Mongo daemon hit ctrl-c

Reference

Install MongoDB Community Edition on macOS