fields_for

1 一对多

Using Strong Parameters With Fields For & Nested Forms in Rails 4
http://www.rubyexperiments.com/using-strong-parameters-with-nested-forms/
class Account < ActiveRecord::Base
  has_many :people
  accepts_nested_attributes_for :people
end
class Person < ActiveRecord::Base
  belongs_to :account
end
class AccountsController < ApplicationController
  def new
    @account = Account.new
     @account.people.build  （一对多这样写）          http://www.tuicool.com/articles/Jjee6v （rails 中 create, new, build, save 的用法）
  @account.build_people （一对一这样写）
  end
  def create
    @account = Account.new(new_account_params)
    if @account.save
      respond_to do |format|
        format.html { redirect_to root_path, notice: "Account created successfully." }
      end
    end
  end

  private

  def new_account_params
    params.require(:account).permit( :id, :name, people_attributes: [:id, :email, :password, :password_confirmation] )
  end
end

 <% form_for @accountdo |f| %>
    <%= f.text_field :name %>
    <% f.fields_for :people do |pf| %> #注意这里
      <%= pf.text_field :email %>
    <% end %>
 <% end %>