将用户与角色模型关联时的Rails嵌套字段

class User < ApplicationRecord
  has_many :roles
  accepts_nested_attributes_for :roles
end

class UsersController < ApplicationController
  def new
    @user = User.new
    @user.roles.build
  end

  def create
    @user = User.new(user_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, roles_attributes: [:name])
  end
end

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

  <%= f.fields_for :roles do |role_fields| %>
    <%= role_fields.label :name %>
    <%= role_fields.text_field :name %>
  <% end %>

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