Question

根据下面我认为这个设置很好：

class Location < ActiveRecord::Base
  has_many :traders
  has_many :servicelocations
  has_many :services, through: :servicelocations
end

class Service < ActiveRecord::Base
    has_many :servicelocations
    has_many :locations, through: :servicelocations
end

class ServiceLocation < ActiveRecord::Base
    belongs_to :location
    belongs_to :service
end

class Trader < ActiveRecord::Base
  belongs_to :location
end

问题是我仍然得到uninitialized constant error。

我注意到，当我创建模型ServiceLocation时，funky rails magic创建了service_location.rb，但我不确定是否a）这是问题，b）如果它是如何修复它。

Answer 1

我猜ruby明白servicelocations就像一个单词，因此您需要将模型更改为Servicelocation或将关联更改为service_locations。第二种方法我认为更好，它会像：

class Location < ActiveRecord::Base
  has_many :traders
  has_many :service_locations
  has_many :services, through: :service_locations
end

class Service < ActiveRecord::Base
  has_many :service_locations
  has_many :locations, through: :service_locations
end

Answer 2

我相信你的错误来自于此

class Service < ActiveRecord::Base
    has_many :servicelocations
    has_many :locations, through: :servicelocations
end

这些应该是这样的

class Service < ActiveRecord::Base
    has_many :service_locations
    has_many :locations, through: :service_locations # notice the underscore
end

您的模型类名称为ServiceLocation，其轨道约定名称为service_location而非servicelocation

在这里，你必须改变

class Location < ActiveRecord::Base
  has_many :traders
  has_many :service_locations
  has_many :services, through: :service_locations
end

多元化的多对多但仍然未初始化的常数

2 个答案: