Question

大家。我试图将每个产品与他的类别联系起来。但是有一些错误。

所以，起初。以下是我的产品和类别迁移：

class CreateProducts < ActiveRecord::Migration
   def change
      create_table :products do |t|
          t.belongs_to :categoty, index: true
          t.string :title
          t.string :category
          t.text :description
          t.string :image_url
          t.decimal :price, precision: 8, scale: 2
          t.timestamps
      end
   end
end


class CreateCategories < ActiveRecord::Migration
  def change
    create_table :categories do |t|
      t.references :product
      t.string :name
      t.timestamps null: false
    end
  end
end

它们都在模型中有关联（产品为belongs_to，类别为has_many。

我已将表格与此类别的产品相关联：

<div class="field">
  <%= f.collection_select :category, Category.all, :id, :name %>
</div>

当我试图保存产品时出现错误：类别（#XXXX）预期，得到String（#XXXX）。

那么，我做错了什么？

此外，这是我的控制器。

class ProductsController < ApplicationController


    before_action :set_product, only: [:show, :edit, :update, :destroy]


      # GET /products
      # GET /products.json
      def index
        @products = Product.all
      end

      # GET /products/1
      # GET /products/1.json
      def show
      end

      # GET /products/new
      def new
        @product = Product.new
      end

      # GET /products/1/edit
      def edit
      end

      # POST /products
      # POST /products.json
      def create
        @product = Product.new(product_params)

        respond_to do |format|
          if @product.save
            format.html { redirect_to @product, notice: 'Product was successfully created.' }
            format.json { render :show, status: :created, location: @product }
          else
            format.html { render :new }
            format.json { render json: @product.errors, status: :unprocessable_entity }
          end
        end
      end

      # PATCH/PUT /products/1
      # PATCH/PUT /products/1.json
      def update
        respond_to do |format|
          if @product.update(product_params)
            format.html { redirect_to @product, notice: 'Product was successfully updated.' }
            format.json { render :show, status: :ok, location: @product }
          else
            format.html { render :edit }
            format.json { render json: @product.errors, status: :unprocessable_entity }
          end
        end
      end

      # DELETE /products/1
      # DELETE /products/1.json
      def destroy
        @product.destroy
        respond_to do |format|
          format.html { redirect_to products_url, notice: 'Product was successfully destroyed.' }
          format.json { head :no_content }
        end
      end

      private
        # Use callbacks to share common setup or constraints between actions.
        def set_product
          @product = Product.find(params[:id])
        end

        # Never trust parameters from the scary internet, only allow the white list through.
        def product_params
          params.require(:product).permit(:title, :category, :description, :image_url, :price)
        end
    end

Answer 1

在数据库迁移文件中，您有字段categoty，并且您在控制器中使用category_id。只需将字段更改为数据库中的category，以确保它与正确的模型相关联。

无法正确关联产品和类别

1 个答案: