你如何从Rails中的另一个模型中调用一个模型？

Question

我有两个型号，房间和布局。

Layout has_many :rooms
Room belongs_to :layout

房间里有吸烟的布尔值。布局有占用数量。

在Room类中，我想要一个基于smoking和occupancy_count变量返回房间列表的方法。例如，我想搜索可容纳至少4人的吸烟室，或者正好容纳2人的非吸烟房等。

然而，我不能为我的生活弄明白。

在房间模型中，我试过......

def self.rooms_with_occupancy_and_smoking(occupancy_count, smoking)
    layouts = Layout.layouts_with_occupancy_count_gt(occupancy_count) //method self explanatory
    Room.rooms_with_smoking(smoking).joins(layouts) //method self explanatory
end

然而，我得到了一个

Runtime Error: Unknown Class : Layout (specifically when running the second line in that method)

我该如何正确地做这样的事情？

=========型号============

class Layout < ActiveRecord::Base
    has_many :rooms

    validates :description, presence: true
    validates :occupancy_count, presence: true

    def self.layouts_with_occupancy_count(occupancy_count)
        self.where('occupancy_count = ?', occupancy_count)
    end

    def self.layouts_with_occupancy_count_gt(occupancy_count)
        self.where('occupancy_count >= ?', occupancy_count)
    end

    def self.rooms_with_layout(layout_id)
        self.where(id: layout_id).rooms
    end
end


class Room < ActiveRecord::Base
  belongs_to :hotel
  belongs_to :layout
  has_many :visits

  validates :number, presence: true
  validates :rate, presence: true
  #validates :smoking, presence: true

  def self.rooms_with_smoking(smoking)
    self.where('smoking = ?', smoking)
  end

  def self.occupied_rooms(from_date, to_date)
    self.joins(:visits).where('date >= ? and date <= ?', from_date, to_date).uniq
  end

  def self.vacant_rooms(from_date, to_date)
    self.where.not(id: Room.occupied_rooms(from_date, to_date))
  end

  def self.find_rooms_with(occupancy_count, smoking, from_date, to_date)
    Room.vacant_rooms(from_date, to_date).joins(:layout).where('occupancy_count >= ?', occupancy_count).where('smoking = ?', smoking)
  end  

  def self.rooms_with_occupancy_and_smoking(occupancy_count, smoking)
    layouts = Layout.layouts_with_occupancy_count_gt(occupancy_count) //method self explanatory
    Room.rooms_with_smoking(smoking).joins(layouts) //method self explanatory
  end

  def self.blahblah(occupancy_count, smoking, from_date, to_date)
    layouts = Layout.layouts_with_occupancy_count_gt(occupancy_count)
    Room.rooms_with_smoking(smoking).vacant_rooms(from_date, to_date).joins(layouts)
  end

  def self.lowest_room_rate(hotel_id)
    self.where('hotel_id = ?', hotel_id).select(:rate).order(:rate).first
  end

  def self.highest_room_rate(hotel_id)
    self.where('hotel_id = ?', hotel_id).select(:rate).order(:rate).last
  end
end