Rails：ActiveRecord :: HasManyThroughSourceAssociationNotFoundError：找不到源关联
我有以下代码（有点简化……
create_table :signatures do |t| t.integer :signer_id t.integer :card_id t.timestamps end 模型看起来像……
class Signature < ActiveRecord::Base belongs_to :card belongs_to :user end class Card :signatures, :foreign_key => "card_id" end class User "Card", :foreign_key => "sender_id" has_many :received_cards, :class_name => "Card", :foreign_key => "recipient_id" has_many :signatures has_many :signed_cards, :through => :signatures, :foreign_key => "signer_id" end
我使用rails控制台看到以下错误…
ruby-1.9.2-p0 > u15.signed_cards ActiveRecord::HasManyThroughSourceAssociationNotFoundError: Could not find the source association(s) :signed_card or :signed_cards in model Signature. Try 'has_many :signed_cards, :through => :signatures, :source => '. Is it one of :card or :user? from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/reflection.rb:517:in `check_validity!' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/associations/association.rb:27:in `initialize' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/associations/collection_association.rb:24:in `initialize' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/associations.rb:164:in `new' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/associations.rb:164:in `association' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.1.0/lib/active_record/associations/builder/association.rb:41:in `block in define_readers' from (irb):11 from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.1.0/lib/rails/commands/console.rb:45:in `start' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.1.0/lib/rails/commands/console.rb:8:in `start' from /home/slabounty/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.1.0/lib/rails/commands.rb:40:in `' from script/rails:6:in `require' from script/rails:6:in `'
当我添加source => :card/:user时，我会得到同样的东西（应该是：卡片，在这种情况下我相信）。
我在这里做错了什么想法？
显示部分解决方案，因为我想清理一些东西。 迁移与以前的版本保持一致。 我现在看到一个SQL错误（见下文），它在Signature中找不到user_id。 我讨厌这么说，但大多数时候我一直在投入：foreign_key，我觉得它们可能无济于事。
class Signature "User" end class Card :signatures, :source => :user end class User "signer_id" has_many :signed_cards, :through => :signatures, :source => :card end
带错误（减去堆栈跟踪）
ruby-1.9.2-p0 > u15.signed_cards Card Load (0.5ms) SELECT "cards".* FROM "cards" INNER JOIN "signatures" ON "cards"."id" = "signatures"."card_id" WHERE "signatures"."user_id" = 15 ORDER BY cards.created_at DESC SQLite3::SQLException: no such column: signatures.user_id: SELECT "cards".* FROM "cards" INNER JOIN "signatures" ON "cards"."id" = "signatures"."card_id" WHERE "signatures"."user_id" = 15 ORDER BY cards.created_at DESC ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: signatures.user_id: SELECT "cards".* FROM "cards" INNER JOIN "signatures" ON "cards"."id" = "signatures"."card_id" WHERE "signatures"."user_id" = 15 ORDER BY cards.created_at DESC
Card.signers按预期返回一个空数组。
还在寻找这方面的一些帮助。 我没有找到很多简单，直接的解释，你没有使用相同的名称（即你需要一个foreign_key和source。
用户应该这样定义：
class User < ActiveRecord::Base has_many :sent_cards, :class_name => "Card", :foreign_key => "sender_id" has_many :received_cards, :class_name => "Card", :foreign_key => "recipient_id" has_many :signatures has_many :signed_cards, :through => :signatures, :source => :card end
当您的关联名称与以下名称使用的名称不同时，您必须定义源参数。 如果您查看exception消息，它会明确要求您执行此操作。
好吧，因为我有这么难的时间，我想向大家展示最终版本的样子。 我很难解决这个问题的一个很好的部分原因是，当我做出更改时，rails控制台似乎没有正确地重新加载东西。 我没有意识到这一点，直到我放弃了一个晚上，第二天早上回来，前一天晚上工作的案件没有，而且那个案件没有用。
迁移是一样的，但为了完整起见，我会重复它。
def change create_table :signatures do |t| t.integer :signer_id t.integer :card_id t.boolean :signed, :default => false t.text :message t.timestamps end end
Signature类具有两个belongs_to，其中卡通常在示例中显示，签名者是user类型。
class Signature < ActiveRecord::Base belongs_to :card belongs_to :signer, :class_name => "User" end
用户有很多签名（即使你不直接使用它们也是必需的）一个带有卡片源签名的dmany signed_cards（告诉Rails类似signed_cards的类型）。
class User < ActiveRecord::Base has_many :signatures, :foreign_key => "signer_id" has_many :signed_cards, :through => :signatures, :source => :card end
最后，卡片有许多签名（再一次是必要的）和许多签名者签名和signer_id签名者的foreign_key。
class Card < ActiveRecord::Base has_many :signatures has_many :signers, :through => :signatures, :foreign_key => 'signer_id' end
希望这可以帮助其他人遇到类似的问题。