标签: rails-activerecord

我正在构建一个 Rails 锻炼应用程序，其中包含练习和例程。我希望每个例程都由多个练习组成（has_many :exercises），但一个练习不一定必须属于一个例程。有没有办法做到这一点？

我想在我的控制台中调用它（ap是很棒的打印宝石）：

ap Purchase.last(10)

但我收到此错误：

ActionController::UnfilteredParameters: unable to convert unpermitted parameters to hash

它的工作原理如下：

irb(main):020:0> ap Purchase.last
#<Purchase:0x00007f86b792a320> {
                              :id => 28445,
                         :user_id => 10177,
                      :product_id => nil,
                    :product_type => nil,
                           :price => 9.0,
                    :gateway_code => nil,
                     :gateway_msg => nil,
                :gateway_response => nil,
                      :created_at => Fri, 18 May 2018 22:20:10 UTC +00:00,
                      :updated_at => Fri, 18 May 2018 22:20:10 UTC +00:00,
                  :checkout_total => 9.0,
                      :successful => true,
                         :cart_id => 17242,
                   :report_errors => nil,
    :transacted_value_of_products => 9.0,
            :comp_credits_applied => 0.0 …

我是 Rails 新手。更改表名称时遇到问题。

我尝试通过转到迁移文件来更改名称create_table，并从那里更改名称，但它不起作用。

所以我有@cake.type，它可以是“Primo”、“Multilayered”、“Decorative”、“On Sale”、“Basic”`

我想按该顺序组织蛋糕列表。因此，所有“Primo”蛋糕都位于顶部，接下来是所有“多层”蛋糕，等等。每种类型的蛋糕都应按“created_at”进一步列出（最旧创建的蛋糕在前）。

@cakes = []
@cakes << @store.cakes.where(type: "Primo").order(created_at: :desc) 
@cakes << @store.cakes.where(type: "Multilayered").order(created_at: :desc) 
@cakes << @store.cakes.where(type: "Decorative").order(created_at: :desc) 
@cakes << @store.cakes.where(type: "On Sale").order(created_at: :desc) 
@cakes << @store.cakes.where(type: "Basic", "Basic").order(created_at: :desc) 

有没有一种方法可以通过一个查询来完成它？

... 或许：

cake_eater_nom = []

c = @store.cakes
primo_cakes = c.where(type: "Primo").order(created_at: :desc)
cake_eater_nom << primo_cakes
multilayered_cakes = c.where(type: "Multilayered").order(created_at: :desc) 
cake_eater_nom << multilayered_cakes
decorative_cakes = c.where(type: "Decorative").order(created_at: :desc) 
cake_eater_nom << decorative_cakes
on_sale_cakes = c.where(type: "On Sale").order(created_at: :desc)
cake_eater_nom << on_sale_cakes
basic_cakes = c.where(type: "Basic").order(created_at: :desc) …