如何列出与某个类别相关的所有文章？

Question

In my RoR app I have a problem with listing all items of a certain category. Here is 2 models:

class Article < ApplicationRecord
  belongs_to :category

and 

class Category < ApplicationRecord
  has_many :articles
end

and my Category controller method :

  def show
    @articles = @category.articles
    @category = Category.find(params[:id])
  end

In db i have relation beetween categories and articles:

create_table "articles", force: :cascade do |t|
    t.string "title"
    t.text "text"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.string "category_id"
  end

  create_table "categories", force: :cascade do |t|
    t.string "name"
    t.text "desc"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

And in my article index view page have code where on link ("Category") name I want to show all articles of certain category

  <td>
    <% if article.category %>
      <%= link_to article.category.name, category_path %>
    <% end %>
  </td>

But I receive error

No route matches {:action=>"show", :controller=>"categories"}, missing required keys: [:id]

Answer 1

您必须提供响应id方法的id或category对象才能生成正确的链接：

<%= link_to article.category.name, category_path(article.category) %>