agile web development with rails 1

Building an application
word> rails new depot
depot> rails server
depot> rails generate scaffold Product title:string description:text image_url:string price:decimal
depot> rake db:migrate
<%= f.text_area :description, :rows => 6 %>     #html text_area为6行

/depot/db/seeds.rb:

Product.delete_all
Product.create(:title => 'Web Design for Developers',
  :description => 
    %{

        Web Design for Developers will show you how to make your
        web-based application look professionally designed. We'll help you
        learn how to pick the right colors and fonts, avoid costly interface
        and accessibility mistakes -- your application will really come alive.
        We'll also walk you through some common Photoshop and CSS techniques
        and work through a web site redesign, taking a new design from concept
        all the way to implementation.
      
},
  :image_url =>   '/images/wd4d.jpg',    
  :price => 42.95)

depot> rake db:seed   #添加数据到数据库

将图片放到该目录depot_b/public/images，用/images/1.jpg即可访问

将css文件放到depot/public/stylesheets/depot.css，视图文件即可调用。

Validation

加入models/product.rb:
validates :title, :description, :image_url, :presence => true     # :presence => true 即不为空

validates :price, :numericality => {:greater_than_or_equal_to => 0.01}    # 验证数字，并且大于等于0.01

validates :title, :uniqueness => true   #唯一

validates :image_url, :format => {
:with => %r{\.(gif|jpg|png)$}i,
:message => 'must be a URL for GIF, JPG or PNG image.'
}
#以什么结尾，加错误提示