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chiastolite/gist:4b95d88811b6355ae540

Last active August 29, 2015 14:24
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こういうhas_oneの使い方ってありなんだろうか?
Raw
gistfile1.rb
class Entry < ActiveRecord:Base
has_many :messages
has_one :latest_message, -> { merge(Message.latest) }, class_name: 'Message'
end
class Message < ActiveRecord:Base
scope :latest, -> { order(id: :desc) }
end
Raw
gistfile2.txt
irb(main):003:0> @entry = entry.first
Entry Load (0.2ms) SELECT "entries".* FROM "entries" ORDER BY "entries"."id" ASC LIMIT 1
irb(main):003:0> @entry.latest_message
Message Load (0.2ms) SELECT "messages".* FROM "messages" WHERE "messages"."entry_id" = ? ORDER BY "messages"."id" DESC LIMIT 1 [["entry_id", 1]]
=> #<Message id: 10, body: "Message9", entry_id: 1, created_at: "2015-06-30 16:06:47", updated_at: "2015-06-30 16:06:47">
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よいらしい
編集しないからreadonlyしたほうがいいとのこと

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