修改environment.rb 記得要
restart application

不是 web server
<br/>才有真正換行 <%=%> 沒有Object/Relational Mapping
ORM 把datebase table mapping 到class。如果有database table叫orders, 那就有相對應個class叫做Order. tables correspond to classes. rows in a table correspond to objects of the class
example:
order = Order.find(1)
puts "Order #{order.custom_id}, amount=#{order.amount}"
Order.find(:all, :conditions => "name='lake'") do |order|
puts order.amount
order.discount = 0.5
order.save
end