Google Reader

rails 3 generate scaffold 会用到

by

at 2011-06-08 22:49:32

original http://hlee.iteye.com/blog/1073636

一个可能要知道model的数据格式都支持什么
可以支持的数据类型

一个是如果要是创建完了，发现不满意怎么办呢

例如，运行如下：

rails g scaffold task project_id:integer name:string

我的话，第一想到的是git checkout或者git reset
实际上，用如下更合适

rails destroy scaffold task

那么，要是生成了scaffold并且，用了一段了时间了呢

可以先把数据库版本退回来

rake db:rollback STEP=3

当然，通常有数据就不建议rollback了，就要

就要

rails generate migration AddPartNumberToProducts part_number:string

class AddPartNumberToProducts < ActiveRecord::Migration
  def self.up
    add_column :products, :part_number, :string
  end


  def self.down
    remove_column :products, :part_number
  end
end

rails generate migration RemovePartNumberFromProducts part_number:string

class RemovePartNumberFromProducts < ActiveRecord::Migration
  def self.up
    remove_column :products, :part_number
  end


  def self.down
    add_column :products, :part_number, :string
  end
end

class ExampleMigration < ActiveRecord::Migration


  def self.up
    create_table :products do |t|
      t.references :category
    end
    #add a foreign key
    execute <<-SQL
      ALTER TABLE products
        ADD CONSTRAINT fk_products_categories
        FOREIGN KEY (category_id)
        REFERENCES categories(id)
    SQL

add_column :users, :home_page_url, :string

rename_column :users, :email, :email_address


  end

  def self.down
    rename_column :users, :email_address, :email
    remove_column :users, :home_page_url
    execute "ALTER TABLE products DROP FOREIGN KEY fk_products_categories"
    drop_table :products
  end
end

参考：
http://asciicasts.com/episodes/216-generators-in-rails-3
http://guides.rubyonrails.org/migrations.html
http://www.viget.com/extend/rails-3-generators-the-old-faithful/

          <br><br>
          <span style="color:red">
            <a href="http://hlee.iteye.com/blog/1073636#comments" style="color:red">已有 <strong>1</strong> 人发表留言，猛击-&gt;&gt;<strong>这里</strong>&lt;&lt;-参与讨论</a>
          </span>
          <br><br><br>

ITeye推荐

• —软件人才免语言低担保 赴美带薪读研！—