Rails 3:多个has_one关联和种子

Question

我正在使用Rails似乎没有做到的数据概念 - 一条路线有两个(也就是两个)机场.我终于想出了如何对我的外键进行硬编码以使它们变得合情合理.

我models/route.rb很简单:

class Route < ActiveRecord::Base
  has_one :airport, :foreign_key => 'from_airport_id', :class_name => 'Airport'
  has_one :airport, :foreign_key => 'to_airport_id', :class_name => 'Airport'
end

这一切似乎工作正常,但我似乎无法正确播种.

我seeds.rb看起来像这样:

Airport.delete_all
@kpdx = Airport.create(:icao => 'KPDX', :name => 'Portland International Airport', :lat => '45.58869934', :lon => '-122.5979996')
@ksea = Airport.create(:icao => 'KSEA', :name => 'Seattle Tacoma International Airport', :lat => '47.4490013122559', :lon => '-122.30899810791')
Route.delete_all
Route.create(:from_airport_id => @kpdx, :to_airport_id => @ksea, :route => "RIVR6 BTG OLM6")
Route.create(:from_airport_id => @kpdx, :to_airport_id => @ksea, :route => "BTG OLM OLM6")

Route.create(:from_airport_id => Airport.find_by_icao("KSEA"), :to_airport_id => Airport.find_by_icao("KPDX"), :route => "SEATL4 SEA HELNS4")
Route.create(:from_airport_id => Airport.find_by_icao("KSEA"), :to_airport_id => Airport.find_by_icao("KPDX"), :route => "SEA HELNS4")

请注意,我有两种不同的方法可以告诉种子数据从我创建的一个机场到另一个机场.两者都不起作用.当我运行时,当表中的ID 递增时(在我当前运行中为23和24)rake db:seed,所有from_airport_id和to_airport_id字段都设置为1 airport.

所以我有两个问题:

1. 有没有比我正在做的更好的方法来处理模型代码？
2. 播种时我做错了什么:-)

谢谢!

Answer 1

我会改变你的模型,为每个关系指定一个不同的符号:

class Route < ActiveRecord::Base
  has_one :from_airport, :foreign_key => 'from_airport_id', :class_name => 'Airport'
  has_one :to_airport, :foreign_key => 'to_airport_id', :class_name => 'Airport'
end

由于启用a has_one允许您通过名称(例如route.airport)访问该关系,因此这些需要不同.

要让您的播种工作,请致电.id机场:

Route.create(:from_airport_id => @kpdx.id, :to_airport_id => @ksea.id, :route => "RIVR6 BTG OLM6")

例:

ruby-1.9.2-p136 :001 > a = Airport.create(:icao => 'KPDX', :name => 'Portland International Airport')
 => #<Airport id: 1, icao: "KPDX", name: "Portland International Airport", created_at: "2011-03-01 02:44:42", updated_at: "2011-03-01 02:44:42">
ruby-1.9.2-p136 :002 > b = Airport.create(:icao => 'ABCD', :name => 'Another Airport')
 => #<Airport id: 2, icao: "ABCD", name: "Another Airport", created_at: "2011-03-01 02:46:22", updated_at: "2011-03-01 02:46:22">
ruby-1.9.2-p136 :003 > r = Route.create(:to_airport_id => a.id, :from_airport_id => b.id)
 => #<Route id: 3, from_airport_id: 2, to_airport_id: 1, route: nil, created_at: "2011-03-01 02:46:36", updated_at: "2011-03-01 02:46:36">