How can I connect to MySQL in Ruby on Rails?

问题

I am really new in Ruby on Rails. I have read this tutorial and it sounds really easy.

But how can I connect to my database (MySQL) or what does Rails use? In php I'd use...

mysql_connect("...","...","...");
mysql_select_db("...");

I have searched google and cannot find any useful tips.

回答1:

You don't have to do those things manually, check this: http://guides.rubyonrails.org/configuring.html#configuring-a-database

回答2:

Have a look into the configuration file config/database.yml

You need to setup your configuration there. Here is an example for the production environment:

production: 
   adapter: mysql2
   encoding: utf8 
   database: example 
   pool: 10 
   username: example 
   password: secure 
   socket: /var/run/mysqld/mysqld.sock 
   reconnect: true

In addition to that you have to add gem 'mysql2' in your Gemfile and run bundle install.

回答3:

Contents of my config/database.yml file:

# Ensure the MySQL gem is defined in your Gemfile
#   gem 'mysql2'
#
# Install MySql gem if not already there.
# Below command installs some pre-requisites for the installation:
#   sudo apt-get install libmysqlclient-dev mysql-client
# After above, this to finish gem installation:
#   gem install mysql2
#
# And be sure to use new-style password hashing:
#   http://dev.mysql.com/doc/refman/5.0/en/old-client.html

development:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: YOUR_DATABASE_HERE
  pool: 5
  username: root
  password: root

As the comments above the configurations say, you might need to install the mysql2 gem first via the terminal. After installation is finished, do a bundle install and rake db:migrate and can then access the database via phpmyadmin too.

I had just stumbled upon this question an hour ago, more than 2 years later since the question was asked. Although I understand this is very late and for sure OP must have solved this, for the sake of other beginner users like me who might be coming here for a solution, I thought of writing my solution here. Hope it helps.

来源：https://stackoverflow.com/questions/15613646/how-can-i-connect-to-mysql-in-ruby-on-rails