[Ruby] Rails DB PostgreSQL changed to MySQL

1 minute read


Up to now, I used PostgreSQL to deploy to the database in the database, but if it is heroku, the mysterious phenomenon that the posted image disappears after a certain time occurs.

That’s why I decided to deploy it on AWS and change the database to MySQL, so I will try it.


I have already installed MySQL. If you haven’t already, please install it.

Then add gem'mysql2' to the Gemfile.


default: &default
  adapter: mysql2
  encoding: utf8
  username: root

Open database.yml and rewrite.

If you are installing it for the time being when learning somewhere like me, I think that you probably have not set the password as the root user, so add username: root and password: at this time. ..

If you have created a user and want to log in, I think that it is better to enter the username and password. (maybe)

$ bundle install

Install it.

$ bundle exec rake db:create

Create a database

$ rails db:migrate

Don’t forget this command!

It is not particularly difficult when I actually try it, but I thought that if I do not understand it I might be crazy. (Because I was addicted)

It seemed difficult to change the DB from the perspective of a beginner, but it was unexpectedly smooth, so it is important to challenge!