图片控制器中的 ActiveRecord::UnknownAttributeError#create

Question

我正在尝试实现图片上传功能（没有 gem），当我在选择照片后按提交时出现此错误：

Ac
tiveRecord::UnknownAttributeError in PicturesController#create
unknown attribute 'picture' for Picture.

Extracted source (around line #13):

  def create
    # make a new picture with what picture_params returns (which is a method we're calling)
    **@picture = Picture.new(picture_params)** << where i'm getting the error
    if @picture.save
      # if the save for the picture was successful, go to index.html.erb
      redirect_to pictures_url

如何设置我的环境以便我的照片保存在数据库中？

控制器：

class PicturesController < ApplicationController

  def index
    @pictures = Picture.all
  end

  def new
    @picture = Picture.new
  end

  def create
    # make a new picture with what picture_params returns (which is a method we're calling)
    @picture = Picture.new(picture_params)
    if @picture.save
      # if the save for the picture was successful, go to index.html.erb
      redirect_to pictures_url
    else
      # otherwise render the view associated with the action :new (i.e. new.html.erb)
      render :new
    end
  end

  def show
    @picture = Picture.find(params[:id])
  end

  def edit
    @picture = Picture.find(params[:id])
  end

  def update
    @picture = Picture.find(params[:id])

    if @picture.update_attributes(picture_params)
      redirect_to "/pictures/#{@picture.id}"
    else
      render :edit
    end
  end

  def destroy
    @picture = Picture.find(params[:id])
    @picture.destroy
    redirect_to pictures_url
  end

  private
  def picture_params
    params.require(:picture).permit(:artist, :title, :url, :picture)
  end

end

迁移：

class CreatePictures < ActiveRecord::Migration
  def change
    create_table :pictures do |t|
      t.string :artist
      t.string :title
      t.string :url
      t.string :pictures

      t.timestamps null: false
    end
  end
end

我通过编辑文件手动添加了 t.string :pictures，它仍然以这种方式工作还是我需要运行命令？

我的表格：

<container>
<center>
<%= form_for @picture do |f| %>
  <input type="file" multiple>  <%= f.file_field :picture %>
  <p>Drag your files here or click in this area.</p>
  <button type="submit"> <%= f.submit "Save" %> Upload </button>
</form>
<% end %>
</container>

我正在使用简单的拖放上传。 感谢您的帮助，我真的很感激！

Answer 1

PictureController#create 中的 ActiveRecord::UnknownAttributeError

图片的未知属性“图片”

您的迁移文件中有:pictures 而不是:picture，并且您在picture_params 方法中使用:picture。

rake db:rollback，改成:picture，rake db:migrate