db/migrate/20081024180108_create_exchange_rates.rb
class CreateExchangeRates < ActiveRecord::Migration
def self.up
create_table :exchange_rates, :force => true do |t|
t.string :source_currency
t.string :target_currency
t.float :rate
t.timestamps
end
add_index :exchange_rates, [:source_currency, :target_currency, :created_at], :name => :exchange_rates_index
end
def self.down
drop_table :exchange_rates
end
end