扶手：有什么不对的多与协会的条件加入？ [英] rails : what's wrong with this multiple join with conditions on the associations?

问题描述

下面是我的模型：

class Deck < ActiveRecord::Base
  belongs_to :game
  has_many :deck_cards
end

class DeckCard < ActiveRecord::Base
  belongs_to :card
  belongs_to :deck
end

class Card < ActiveRecord::Base
end

下面是我的尝试发现：

DeckCard.all :joins => [:card, :deck], :conditions => {{:decks => {:game_id => @game.id}}, {:cards => {:present => true}}}

我不断收到错误：未定义的方法所有的#Class：0x4b2a98>。我假设这是我的分析条件，误导性的错误。我下面的活动记录查询指南。我不知道是否要使用该协会的单数或复数形式。看起来像一个belongs_to的，你应该在用单数形式：哈希联接，但我不知道的：条件散列，所以我想这两个既不工作

I keep getting the error : undefined method for all for #Class:0x4b2a98>. I'm assuming this is a misleading error from parsing my conditions. I'm following the guide for Active Record Query. I wasn't sure about whether to use the singular or plural form of the associations. Look like with a belongs_to, you're supposed to use singular form in the :joins hash, but I wasn't sure in the :conditions hash, so I tried both and neither worked.

在情况下，它是不明确的，我想要做的SQL是：

In case it isn't clear, what I'm trying to do in SQL is:

SELECT * from DeckCards  
INNER JOIN decks on decks.id = deck_cards.deck_id  
INNER JOIN cards on card.id = deck_cards.card_id  
WHERE decks.game_id = 4  
AND cards.present = true

我能够解决它现在使用 DeckCard.find_by_sql ，但它会是不错的找出原因的加入和关联条件不工作。

I'm able to get around it for now by using DeckCard.find_by_sql, but it would be nice to figure out why the joins and conditions on associations isn't working.

我使用InstantRails的-2.0在Windows上，这是使用Rails 2.0.2

I'm using InstantRails-2.0 on windows, which is using Rails 2.0.2

编辑：（：所有...）而不是使用 DeckCard.find一些进展。我还编辑基于另一个答案的括号内。我最近code是

Edited : some progress using DeckCard.find(:all ...) instead. I also edited the brackets based on another answer. My latest code is

DeckCard.find :all, :joins => [:card, :deck], :conditions => {:deck => {:game_id => @game.id}, :cards => {:present => true}}

这是产生以下错误：

which is producing the following error:

Unknown column 'deck_cards.decks' in 'where clause': SELECT `deck_cards`.* FROM `deck_cards`   INNER JOIN `cards` ON `cards`.id = `deck_cards`.card_id  INNER JOIN `decks` ON `decks`.id = `deck_cards`.deck_id  WHERE (`deck_cards`.`decks` = '--- \n- :game_id\n- 5\n' AND `deck_cards`.`cards` = '--- \n- :present\n- true\n')

这些连接看起来是正确的，但不能在WHERE条件。我试着像一些不同的东西：甲板或：甲板在条件子句中，但没有运气。难道这是当前的ActiveRecord查询接口文档和条件，如何在2.0.2办呢？

The joins appear correct but not the WHERE conditions. I've tried a few different things like :deck or :decks in the conditions clause but no luck. Could this be another difference between the current ActiveRecord Query Interface docs and how conditions are done in 2.0.2?

谢谢！

推荐答案

您需要完成与该卡的型号贵会：

You need to complete your association with the Card model:

class Card < ActiveRecord::Base
  has_many :deck_cards
end

编辑2 ：试试这个：

 DeckCard.find :all, :joins => [:card, :deck], :conditions => ["decks.game_id = ? and cards.present = ?", @game.id, true]

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