Question

Page.find(permalink: 'home')
# => Page.find(permalink: 'home')                                                                                                                        
# => ArgumentError: Unknown key: permalink

Page.where(permalink: 'home')
# => [#<Page id: 1, permalink: "home", content: "foo", created_at: "2014-05-14 01:54:06", updated_at: "2014-05-14 01:54:06">]

路线

get ':permalink', to: 'page#show', as: :page

模型

class Page < ActiveRecord::Base
  validates_uniqueness_of :permalink
end

控制器

class PageController < ApplicationController
  def show
    @page = Page.find(permalink: params[:permalink])
  end

  def new
    @page = Page.new
  end

  def create
    @page = Page.new page_params

    if @page.valid?
      redirect_to @page
    else
      render :new
    end
  end

  def update
    @page = page.find(params[:permalink])

    if @page.update(page_params)
      redirect_to @page
    else
      render :edit
    end
  end

  def edit
    @page = page.find params[:permalink]
  end

  private

  def page_params
    params.require(:page).permit(:permalink, :content)
  end
end

我在这里做些什么吗？

Answer 1

这不是find方法的工作方式。看看the Rails Guide。您传递一个主键，该主键可能在数据库中，也可能不在数据库中，而不是哈希值。 where方法可以采用散列或字符串。

Page.find(1)
# => [#<Page id: 1, permalink: "home", content: "foo", created_at: "2014-05-14 01:54:06", updated_at: "2014-05-14 01:54:06">]

Page.where(permalink: "home", content: "foo")
# => [#<Page id: 1, permalink: "home", content: "foo", created_at: "2014-05-14 01:54:06", updated_at: "2014-05-14 01:54:06">]

未找到Rails Model.find键，找到Model.where键

1 个答案: