How do I check the Database type in a Rails Migration?

Question

I have the following migration and I want to be able to check if the current database related to the environment is a mysql database. If it's mysql then I want to execute the SQL that is specific to the database.

How do I go about this?

 class AddUsersFb < ActiveRecord::Migration    def self.up     add_column :users, :fb_user_id, :integer     add_column :users, :email_hash, :string     #if mysql     #execute("alter table users modify fb_user_id bigint")   end    def self.down     remove_column :users, :fb_user_id     remove_column :users, :email_hash   end  end 

Answer 1

Even more shorter call

ActiveRecord::Base.connection.adapter_name == 'MySQL' 

Answer 2

ActiveRecord::Base.connection will provide you with everything you ever wanted to know about the database connection established by boot.rb and environment.rb

ActiveRecord::Base.connection returns a lot of information. So you've got to know exactly what you're looking for.

As Marcel points out:

ActiveRecord::Base.connection.instance_of?    ActiveRecord::ConnectionAdapters::MysqlAdapter  

is probably the best method of determining if your database MySQL.

Despite relying on internal information that could change between ActiveRecord release, I prefer doing it this way:

ActiveRecord::Base.connection.instance_values["config"][:adapter] == "mysql"