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[Rails]カラムのreference型について

reference型とは

外部キーになるカラムを生成する時にこの型にすることが多い。

使い方

20××××××××××××.rb
class CreateUsers < ActiveRecord::Migration[5.0]
  def change
    create_table :users do |t|
      t.string    :name
      t.references :category, foreign_key: true
    end
  end
end

この場合category_idカラムが生成されます。
reference型は、外部キー制約をつけるときに「foreign_key: true」を使うことで制約が適用される。
※ちなみに、インデックスを自動で張ってくれるため自分で設定する必要はありません。

ren0826jam
プログラミング歴数ヶ月の初心者ですが、よろしくお願いします。
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