Rails 命名约定存在问题

Question

我想我在我的应用程序中遵循了 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。这是我的终端会话：

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

从我的模型来看：

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

我处于停滞状态、卡住、用头撞墙等。任何帮助都会很棒。

Rails 菜鸟在这里......好像这一点并不明显......

Answer 1

注意到您似乎在 IRB 中...相反，在处理活动记录类时，我会尝试留在 Rails 控制台中。

所以从

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之间的链接。在这里，它是 CtaLocation，但如果您不打算实际使用这个模型，您甚至可以不定义它。

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