Rails : has_one和belongs_to相同的模型

class User < ApplicationRecord
  has_one :profile
end

class Profile < ApplicationRecord
  belongs_to :user
end

class CreateUsers < ActiveRecord::Migration[6.0]
  def change
    create_table :users do |t|
      t.string :name
      t.timestamps
    end
  end
end

class CreateProfiles < ActiveRecord::Migration[6.0]
  def change
    create_table :profiles do |t|
      t.string :bio
      t.references :user, foreign_key: true
      t.timestamps
    end
  end
end

# 创建用户和个人资料
user = User.create(name: "John")
profile = Profile.create(bio: "Hello", user: user)

# 查询用户的个人资料
user.profile

# 查询个人资料所属的用户
profile.user