自己参照テーブルに問題があります。
惑星、星、月を保持できるオーブ モデルを入手しました。あるものが別のものを「周回」していることを伝えたい
Railsガイドを見ましたが、うまくいきました
私のモデル:
class Orb < ActiveRecord::Base
belongs_to :orb_type
has_and_belongs_to_many :books
belongs_to :orbit, :class_name => "Orb"
has_many :orbs, :class_name => "Orb", :foreign_key => "orb_id"
attr_accessible :descr, :nome, :orb_type_id, :book_ids, :orb_id
validates :nome, uniqueness: true, presence: true
end
不適切なリレーション名を使用していると思います (おそらく間違った方法で)
1.9.3-p448 :002 > earth = Orb.find(1)
Orb Load (0.2ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."id" = ? LIMIT 1 [["id", 1]]
=> #<Orb id: 1, nome: "Terra", descr: "123123", orb_type_id: 1, created_at: "2013-09-25 14:53:35", updated_at: "2013-09-25 14:57:40", orb_id: nil>
1.9.3-p448 :003 > moon = Orb.find(2)
Orb Load (0.2ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."id" = ? LIMIT 1 [["id", 2]]
=> #<Orb id: 2, nome: "Lua", descr: "asd", orb_type_id: 2, created_at: "2013-09-25 14:53:46", updated_at: "2013-09-25 14:55:31", orb_id: nil>
1.9.3-p448 :004 > sun = Orb.find(3)
Orb Load (0.2ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."id" = ? LIMIT 1 [["id", 3]]
=> #<Orb id: 3, nome: "Sol", descr: "asd", orb_type_id: 3, created_at: "2013-09-25 14:53:55", updated_at: "2013-09-25 14:53:55", orb_id: nil>
1.9.3-p448 :006 > moon.orbit=earth
=> #<Orb id: 1, nome: "Terra", descr: "123123", orb_type_id: 1, created_at: "2013-09-25 14:53:35", updated_at: "2013-09-25 14:57:40", orb_id: nil>
1.9.3-p448 :007 > earth.orbit=sun
=> #<Orb id: 3, nome: "Sol", descr: "asd", orb_type_id: 3, created_at: "2013-09-25 14:53:55", updated_at: "2013-09-25 14:53:55", orb_id: nil>
1.9.3-p448 :008 > earth
=> #<Orb id: 1, nome: "Terra", descr: "123123", orb_type_id: 1, created_at: "2013-09-25 14:53:35", updated_at: "2013-09-25 14:57:40", orb_id: nil>
1.9.3-p448 :009 > sun
=> #<Orb id: 3, nome: "Sol", descr: "asd", orb_type_id: 3, created_at: "2013-09-25 14:53:55", updated_at: "2013-09-25 14:53:55", orb_id: nil>
1.9.3-p448 :010 > moon
=> #<Orb id: 2, nome: "Lua", descr: "asd", orb_type_id: 2, created_at: "2013-09-25 14:53:46", updated_at: "2013-09-25 14:55:31", orb_id: nil>
最終的に何も関連付けられず、FK はまだゼロです。
collun orb_id は、モデルの後半に追加されました。移行をセットアップし、モデルに追加しました。それが私の問題に関連している可能性はないと思います...
編集：
今ではすべてが奇妙です。モデルを次のように変更します。
class Orb < ActiveRecord::Base
belongs_to :orb_type
has_and_belongs_to_many :books
belongs_to :orbit, :class_name => "Orb"
has_many :orbits, :class_name => "Orb", :foreign_key => "orb_id"
attr_accessible :descr, :nome, :orb_type_id, :book_ids, :orb_id
validates :nome, uniqueness: true, presence: true
end
レールコンソール（レールc）で私は試します：
1.9.3-p448 :008 > earth = Orb.find(1)
Orb Load (0.2ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."id" = ? LIMIT 1 [["id", 1]]
=> #<Orb id: 1, nome: "Terra", descr: "", orb_type_id: 1, created_at: "2013-09-25 17:51:26", updated_at: "2013-09-25 18:16:58", orb_id: 3>
1.9.3-p448 :009 > earth.orbit
=> nil
1.9.3-p448 :010 > earth.orbits
Orb Load (0.3ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."orb_id" = 1
=> [#<Orb id: 2, nome: "Lua", descr: "", orb_type_id: 2, created_at: "2013-09-25 17:51:40", updated_at: "2013-09-25 18:17:31", orb_id: 1>]
1.9.3-p448 :011 >
一体何？軌道は私が望むものを返すように見えますが、それを使用しようとしています:
1.9.3-p448 :004 > earth.orbits.nome
NoMethodError: Orb Load (0.4ms) SELECT "orbs".* FROM "orbs" WHERE "orbs"."orb_id" = 1
undefined method `nome' for #<ActiveRecord::Relation:0x00000003d593c0>
from /usr/local/rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.12/lib/active_record/relation/delegation.rb:45:in `method_missing'
from /usr/local/rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.12/lib/active_record/associations/collection_proxy.rb:100:in `method_missing'
from (irb):4
from /usr/local/rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.12/lib/rails/commands/console.rb:47:in `start'
from /usr/local/rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.12/lib/rails/commands/console.rb:8:in `start'
from /usr/local/rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.12/lib/rails/commands.rb:41:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'