Rails系列教程(5)：Active Records

Active Records : 被应用于ORM layer

ORM model : tables map to classes, rows to objects, and columns to object attributes
还是要强调一下，a row maps a object, a table maps a class, a column maps a attribute

Ex:

require 'active_record'

class Order < ActiveRecord::Base
end

# work on business logic

order = Order.find(1)    # fetch the order with an id of 1
order.discount = 0.5
order.save

很显然，这样的实现很直观，不需要考虑到内部如何连接数据库，如何使用SQL语句，一切都变得高效，快速(alige)