How do I set MySQL as the default database in Rails 3?

Question

I started using Rails 2 last April but stopped this June because I thought learning it when Rails 3 was released would be more practical since a lot of it was completely refacto

Answer 1

In tadman's answer, use gem 'mysql2' for the rails 3 since rails 3 now uses the new mysql adapter !!

Answer 2

Since Rails 3.2 you can define a .railsrc file with custom command line options that will always apply to rails new

So, if you create a file called .railsrc and put it in your home directory w/ the contents like this -d mysql it wll make mysql be your default database. You can put any of the command line options in there (including application templates which are supper awesome!)

Run rails new --help from the command line to see all your options.

Answer 3

You can change rails to default to MySql when you generate a new application, but you have to edit a line in your rails installation. You'll have to make the change to every version, and every time you update the rails gem.

I use Ruby-Enterprise. So here's what I do:

In file (where 1.8 is the ruby version and 3.0.4 is the rails version):

/opt/ruby-enterprise/lib/ruby/gems/1.8/gems/railties-3.0.4/lib/rails/generators/rails/app/app_generator.rb

Edit: In rails-3.1.0-rc1 the file is:

gems/railties-3.1.0.rc1/lib/rails/generators/app_base.rb

Search for this line:

class_option :database, :type => :string, :aliases => "-d", :default => "sqlite3",

Change "sqlite3" to "mysql".

class_option :database, :type => :string, :aliases => "-d", :default => "mysql",

So instead of doing:

rails new application_name -d mysql

I can just do (and the database.yml and Gemfiles are configured for the mysql2 gem):

rails new application_name

This assumes you have the correct mysql2 gem installed already. Also, I've only been doing this since Rails 3 came out. It's probably similar for previous versions. Again, every time you update Rails, you'll have to find and edit that file.

Answer 4

In terms of database configuration, nothing much has really changed between Rails 2 and 3 with the exception of how you load your MySQL driver. This used to be done in config/environment.rb but is now done in Gemfile:

gem 'mysql'

The default config/database.yml file is set up with SQLite, but you can easily change this over to be MySQL. A generic version looks like:

defaults: &defaults
  adapter: mysql
  username: localdev
  password: mylocaldevpasswordwhateveritis
  host: localhost

development:
  <<: *defaults
  database: project_dev

test:
  <<: *defaults
  database: project_test

It's the adapter declaration line that sets what driver to use.