如何在Rails 3中创建ActiveRecord无表格模型

Question

我正在尝试创建一个Active Record无表格模型.我的user.rb看起来像这样

class User < ActiveRecord::Base

  class_inheritable_accessor :columns

  def self.columns
    @columns ||= [];
  end

  def self.column(name, sql_type = nil, default = nil, null = true)
    columns << ActiveRecord::ConnectionAdapters::Column.new(
      name.to_s,
      default,
      sql_type.to_s,
      null
    )
  end


  column :name, :text
  column :exception, :text
  serialize :exception      
end

在控制器中创建新对象时

@user = User.new

我收到了错误

Mysql2 ::错误:表'Sampledb.users'不存在:SHOW FIELDS FROM users

Answer 1

class Tableless

  include ActiveModel::Validations
  include ActiveModel::Conversion
  extend ActiveModel::Naming

  def self.attr_accessor(*vars)
    @attributes ||= []
    @attributes.concat( vars )
    super
  end

 def self.attributes
   @attributes
 end

 def initialize(attributes={})
   attributes && attributes.each do |name, value|
     send("#{name}=", value) if respond_to? name.to_sym 
   end
 end

def persisted?
  false
end

def self.inspect
  "#<#{ self.to_s} #{ self.attributes.collect{ |e| ":#{ e }" }.join(', ') }>"
end

end

Answer 2

一些事情:

首先,你正在使用中介绍的方法Rails2 Railscast 193,当你真正应该使用Rails 3的做法,概括Railscast 219

在执行此类操作时,您可能不希望从ActiveRecord :: Base继承.

阅读Yehuda Katz的博客文章.