使用has_one关系创建新的嵌套资源-- Rails 4

class User < ActiveRecord::Base
  has_one :profile
end

rails generate migration CreateProfiles name:string age:integer

rake db:migrate

class UsersController < ApplicationController
  def create
    @user = User.new(user_params)
    @profile = @user.build_profile(profile_params)

    if @user.save
      # 保存成功的处理逻辑
    else
      # 保存失败的处理逻辑
    end
  end

  private

  def user_params
    params.require(:user).permit(:name, :email)
  end

  def profile_params
    params.require(:profile).permit(:name, :age)
  end
end

<%= form_for @user do |f| %>
  <%= f.label :name %>
  <%= f.text_field :name %>

  <%= f.label :email %>
  <%= f.text_field :email %>

  <%= f.fields_for :profile do |p| %>
    <%= p.label :name %>
    <%= p.text_field :name %>

    <%= p.label :age %>
    <%= p.text_field :age %>
  <% end %>

  <%= f.submit %>
<% end %>