在创建Item时关联多个id

G'day伙计们,

我目前正在建立一个测试"拍卖"网站来学习铁路.我已经设置了我的拍卖和用户模型,并且只有经过身份验证的用户才能编辑或删除与他们相关的拍卖.

我遇到的困难是将出价项目与拍卖相关联.

我的模型如下:

class Auction < ActiveRecord::Base
  belongs_to :creator, :class_name => "User"
  has_many :bids
  validates_presence_of :title
  validates_presence_of :description
  validates_presence_of :curprice
  validates_presence_of :finish_time
  attr_reader :bids

  def initialize
    @bids = []
  end

  def add_bid(bid)
    @bids << bid
  end
end

class Bid < ActiveRecord::Base
  belongs_to :auction, :class_name => "Auction", :foreign_key => "auction_id"
  belongs_to :bidder, :class_name => "User", :foreign_key => "bidder_id"

  validates_presence_of :amount
  validates_numericality_of :amount
  @retracted = false
end

class User < ActiveRecord::Base
  has_many :auctions, :foreign_key => "owner_id"
  has_many :bids, :foreign_key => "owner_id" 
#auth stuff here
end

我正在尝试为竞价添加出价记录,但auction_id根本不会添加到记录中.

我使用@auction作为局部变量,在拍卖视图中创建一个具有值的出价.

<% form_for :bid, :url => {:controller => "auction", :action => "add_bids"} do |f|%>

Bid Amount <%= f.text_field :amount %>
<%= submit_tag "Add Bid", :auction_id => @auction %> 
<% end %> 

这连接到以下代码:

def add_bids
    @bid = current_user.bids.create(params[:bid])
   if @bid.save
     flash[:notice] = "New Bid Added"
     redirect_to :action => "view_auction", :id => @bid.auction_id
    end   
 end

我得到的问题是auction_id没有放入bid元素.我已经尝试以HTML格式设置它,但我想我错过了很简单的东西.

我的数据模型,回顾一下

用户既有出价也有拍卖

拍卖有一个用户,并有很多出价

出价有用户并有拍卖

在过去的4个小时里,我一直在努力解决这个问题,而且我开始对这一切感到非常失望.

任何帮助将非常感激!

你并没有完全按照Rails的方式做事,这让你有点混乱.在Rails中成功编码完全是关于约定优于配置.意思是,Rails会猜测你的意思,除非你另有说明.如果猜错了,通常会尝试一些事情.但总的来说,坚持确定性的名字,你会没事的.

你的代码中有很多错误,所以我要清理它并以各种方式发表评论,让你知道什么是错的.

应用程序/模型/ auction.rb

class Auction < ActiveRecord::Base 
  belongs_to :creator, :class_name => "User" 
  has_many :bids 

  # Given the nature of your relationships, you're going to want to add this      
  # to quickly find out who bid on an object.
  has_many :bidders, :through => :bids

  validates_presence_of :title 
  validates_presence_of :description 
  validates_presence_of :curprice 
  validates_presence_of :finish_time attr_reader :bids

  #These two methods are unnecessary.

  # Also don't override initialize in ActiveRecord. Instead use after_initialize

  #def initialize   Supplied by rails when you do has_many :bids 
  #  @bids = []     @bids will be populated by what is picked up from 
  #end              the database based on the has_many relationship

  #def add_bid(bid) Supplied by rails when you do has_many :bids  
  #  @bids << bid   auction.bids << is a public method after has_many :bids   
  #end 
end

应用程序/模型/ bid.rb

class Bid < ActiveRecord::Base 
  # :class_name and :foreign_key are ony necessary when rails cannot guess from a
  # association name. :class_name default is the association singularized and
  # capitalized. :foreign_key default is association_id

  belongs_to :auction #, :class_name => "Auction", :foreign_key => "auction_id" 

  # here we need :class_name because Rails is looking for a Bidder class.
  # also there's an inconsistency. Later user refers to has_many bids with 
  # a foreign_key of owner_id, which one is it? bidder_id or owner_id?
  # if it's owner_id? you will need the :foreign_key option.

  belongs_to :bidder, :class_name => "User" #, :foreign_key => "bidder_id"

  validates_presence_of :amount 
  validates_numericality_of :amount 

  # This will never get called in a useful way.
  # It really should be done in the migration, setting default
  # value for bids.retracted to false

  # @retracted = false 
end

应用程序/模型/ user.rb

class User < ActiveRecord::Base 
  # This makes sense, because an auction can have many bidders, who are also users.

  has_many :auctions, :foreign_key => "owner_id" 

  # This doesn't. A bid belongs to a user, there's no need to change the name. 
  # See above note re: owner_id vs. bidder_id

  has_many :bids, :foreign_key => "owner_id" 

  # You could also use this to quickly get a list of auctions a user has bid on

  has_many :bid_on_auctions, :through => :bids, :source => :auction
  ... auth stuff ...
end

到目前为止一切都那么好吧？

视图不错,但它缺少出价金额的表单部分.此代码假定您将出价值存储在金额列中.我也随意命名为拍卖/出价

应用程序/视图/拍卖/ bid.html.erb

<% form_for :bid, @auction.bids.new do |f|%>
  <%= f.label_for :amount %>
  <%= f.text_field :amount%>


<%= submit_tag "Add Bid" %> 

由表单生成的params哈希:传递给控制器​​:

params = 
  { 
    :bid => 
    { 
      :auction_id => @auction.id
      :amount => value of text_field
     }
  }

你编写它时由from生成的params哈希(注意:我猜名字是因为它们被遗漏在发布的代码之外):

params = 
  { 
    :id => @auction_id ,
    :bid => { :amount => value of text_field }
  }

但是,您的控制器代码是您所有问题的来源,这几乎是完全错误的.我猜这是在拍卖控制器中,这似乎是错误的,因为你正试图创建一个出价.让我们看看为什么:

应用程序/控制器/ auctions_controller.rb

...
def add_bids 
  # not bad, but... @bid will only fill in the owner_id/bidder_id. and bid amount.

  @bid = current_user.bids.create(params[:bid])

  # create calls save, so this next line is redundant. It still works though. 
  # because nothing's happening between them to alter the outcome of save.

  if @bid.save 
    flash[:notice] = "New Bid Added" 

    # you should be using restful routes, this almost works, but is ugly and deprecated.
    # it doesn't work becasue @bid.auction_id is never set. In fact you never use 
    # the auction_id any where, which was in your params_hash as params[:id]
    redirect_to :action => "view_auction", :id => @bid.auction_id
   end
end
...

这是你的控制器应该如何工作.首先,这应该在bid_controller中,而不是auctions_controller

应用程序/控制器/ bids_controller.rb

...
def create
  @bid = Bid.new(params[:bid]) # absorb values from form via params
  @bid.bidder = current_user # link bid to current_user.
  @auction = bid.auction based on.

  # @auction is set, set because we added it to the @bid object the form was based on.

  if @bid.save 
    flash[:notice] = "New Bid Added" 
    redirect_to @auction #assumes there is a show method in auctions_controller
  else 
    render "auctions/show" # or what ever you called the above view
  end
end
...

您还需要确保您的routes.rb中有以下内容(除了可能已存在的内容.这几行将为您设置RESTful路由.

配置/ routes.rb中

ActionController::Routing::Routes.draw do |map|
  ...
  map.resources :auctions
  map.resources :bids
  ...
end

在任何情况下,你都不远.看起来你有一个不错的开始,并且可能会从阅读有关rails的书中获益.如果您不理解底层框架,只是盲目地遵循教程对您没有多大帮助.90%的教程都适用于旧版本的rails并且过时了,这没有任何帮助.

很多代码都是旧的做事方式.特别redirect_to :action => "view_auction", :id => @bid.auction_id和 <% form_for :bid, :url => {:controller => "auction", :action => "add_bids"} do |f|%>.使用RESTful路由,它们会变成redirect_to @auction<%form_for @ auction.bid.new do | f | %>`

这是你应该阅读的资源:

ActiveRecord :: Associations:定义has_many,belongs_to,它们的选项以及它们添加的便捷方法.

了解MVC:更好地理解与Rails相关的信息流

RESTful资源:了解资源.

表单助手:深入描述form_for以及上述代码的工作原理.