Rails 3：多个has_one关联和播种

Question

我正在使用Rails似乎并不擅长的数据概念 - 路由有两个（也是唯一的两个）机场。我终于想出了如何对我的外键进行硬编码，使它们变得明智。

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 

这一切似乎是工作的罚款，但我似乎无法得到它正确地播种。

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") 

注意，我试图告诉种子数据从我创建到其他机场的一个走两种不同的方式。两者都不起作用。当我运行rake db:seed时，from_airport_id和to_airport_id字段的所有字段都设置为1，此时airport表中的ID正在递增（在我当前运行中为23 &）。

所以我有两个问题：

1. 有没有更好的方式来处理比我在做什么型号代码？
2. 我是什么在播种:-)

感谢做错了！

Answer 1

我会改变你的模型，以指定为每个关系的不同的符号：

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has_one，您可以通过名称（例如route.airport）访问的关系，这些都需要是不同的。

为了让您的播种工作，在机场打电话.id：

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

例子：

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">