rails命名约定的问题

Question

我想我已经遵循了我的应用程序中的rails命名约定。但是，当我在终端测试代码时，我遇到了一些违反命名约定的错误。以下是我的终端会话：

irb(main):010:0> a = _
=> #<Neighborhood id: 24, name: "Lincoln Park", created_at: "2011-12-03 20:29:00", updated_at: "2011-12-03 21:08:47", minlat: 41.91092, maxlat: 41.925658, minlng: -87.648761, maxlng: -87.636117>
irb(main):011:0> a.cta_trains
NoMethodError: undefined method `cta_trains' for #<Neighborhood:0x007fd666ee61e8>
    from /usr/local/Cellar/ruby/1.9.2-p290/lib/ruby/gems/1.9.1/gems/activemodel-3.1.1/lib/active_model/attribute_methods.rb:385:in `method_missing'

现在，当我尝试a.CtaTrains时：

irb(main):012:0> a.CtaTrains
  CtaTrain Load (0.4ms)  SELECT "cta_trains".* FROM "cta_trains" INNER JOIN "cta_locations" ON "cta_trains"."id" = "cta_locations"."CtaTrain_id" WHERE "cta_locations"."neighborhood_id" = 24
SQLite3::SQLException: no such column: cta_locations.CtaTrain_id: SELECT "cta_trains".* FROM "cta_trains" INNER JOIN "cta_locations" ON "cta_trains"."id" = "cta_locations"."CtaTrain_id" WHERE "cta_locations"."neighborhood_id" = 24
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: cta_locations.CtaTrain_id: SELECT "cta_trains".* FROM "cta_trains" INNER JOIN "cta_locations" ON "cta_trains"."id" = "cta_locations"."CtaTrain_id" WHERE "cta_locations"."neighborhood_id" = 24

从我的模型中：

class Neighborhood < ActiveRecord::Base

  has_many :cta_trains, :through => :cta_locations
  has_many :cta_locations, :foreign_key => :neighborhood_id

end 

class CtaTrain < ActiveRecord::Base

  has_many :neighborhoods, :through => :cta_locations
  has_many :cta_locations, :foreign_key => :cta_train_id

end

class CtaLocation < ActiveRecord::Base

  belongs_to :neighborhood
belongs_to :cta_train

end

我停滞不前，被卡住了，我的头撞到了墙上，等等。任何帮助都是非常好的。

Rails noobie here....as如果这一点不明显.....

Answer 1

注意到你看起来像是在IRB...相反，在使用活动记录类时，我会尽量留在rails控制台中。

那么就从下面开始

bundle exec rails console

Answer 2

这里你需要的是一个连接表。请参阅关联has_and_belongs_to_many。

连接表将存储某个Neighbourhood和某个CtaTrain之间的链路。在这里，它是CtaLocation，但是如果你不打算实际使用这个模型，你甚至可以不定义它。

例如，您可以使用三个表(neighbourhoods，cta_trains和cta_trains_neighbourhoods)和只有两个模型来实现它，例如：

class Neighbourhood
  has_and_belongs_to_many :cta_trains
end

class CtaTrain
  has_and_belongs_to_many :neighbourhoods
end