Ruby on rails 基于数据库中库存可用性的动态下拉列表-Rails 4

我正在创建一个电子商务网站，我有一个“大小”下拉列表供客户选择大小。我想要的是，下拉菜单只显示根据数据库中的“库存”值可用的大小

有没有人有这样做的经验或有什么见解

在架构中调整表的大小

create_table "sizes", force: true do |t|
    t.integer  "product_id"
    t.integer  "stock"
    t.string   "size"
    t.datetime "created_at"
    t.datetime "updated_at"
end

Size.rb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

类大小

订购产品.rb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

class OrderProduct

Product.rb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

类产品

product/show.html.erb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

---

非常感谢

我希望我完全理解你想要做什么；您应该能够使用

pull

选择所有可用的大小值，如下所示：

@product.sizes.where('stock >= 1').pluck(:size, :id)

---

编辑：参见Douglas F Shearer的文章，scope是一个比在视图中放置Ruby代码更优雅的解决方案

我希望我完全理解你想要做什么；您应该能够使用

pull

选择所有可用的大小值，如下所示：

@product.sizes.where('stock >= 1').pluck(:size, :id)

---

编辑：参见Douglas F Shearer的文章，scope是一个比在视图中放置Ruby代码更优雅的解决方案

在尺寸模型中添加一个范围，并使用该范围填充选择字段

范围：

class Size < ActiveRecord::Base

  belongs_to :product

  scope :in_stock, where('stock > 0')

end

类大小0'）
结束

选择字段：

<%= f.input :size, as: :select, collection: @product.sizes.in_stock, selected: 0, required: false %>

---

在视图中使用范围而不是筛选，可以在其他位置重复使用库存范围，并执行SQL查询，而不是加载所有记录并遍历所有记录。

将范围添加到大小模型中，并使用此来填充选择字段

范围：

class Size < ActiveRecord::Base

  belongs_to :product

  scope :in_stock, where('stock > 0')

end

类大小0'）
结束

选择字段：

<%= f.input :size, as: :select, collection: @product.sizes.in_stock, selected: 0, required: false %>

---

在视图中使用范围而不是过滤，可以让您在其他地方重复使用库存范围，并执行SQL查询，而不是加载所有记录并遍历所有记录。

从@Douglas的答案中得到启发，我发现以下方法可行

Product.rb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

类产品0'）
结束
结束

product/show.html.erb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

---

谢谢你的帮助

从@Douglas的答案中获得灵感，我发现以下方法可行

Product.rb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

类产品0'）
结束
结束

product/show.html.erb

class Size < ActiveRecord::Base

    belongs_to :product
end

class OrderProduct < ActiveRecord::Base

  belongs_to :order
  belongs_to :product
  belongs_to :size
end

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes
end

<%= simple_form_for :basket, url: product_basket_path(@product), remote: true do |f| %>

<%= f.input :quantity, as: :select, collection: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], selected: 1, required: false %>

<%= f.input :size, as: :select, collection: @product.sizes, selected: 0, required: false %>

<%= f.button :submit, "Add to basket" %>

<% end %>

class Product < ActiveRecord::Base

    has_many :order_products
    has_many :orders, through: :order_products
    has_many :sizes

    def in_stock
        self.sizes.where('stock > 0')
    end
end

<%= f.input :size, as: :select, collection: @product.in_stock, selected: 0, required: false %>

---

---

谢谢你的帮助

谢谢@Douglas，这听起来像是两个中比较好的一个。但是，当我将“大”的库存减少到0并查看下拉列表时，它会显示所有大小，包括“大”，但也会显示“小”和“中”，即“小”“中”“大”“小”“中”。有什么想法吗？谢谢，我认为这里的问题是，在我的尺码表中，我有其他尺码为“小”、“中”和“大”的产品，因此它也会在下拉列表中显示这些产品。不确定这里的解决方案是什么？如果您使用@product.size.in_库存，则应该只使用与该产品相关的尺寸。如果出现多个，则每个产品必须有多个相同的尺寸。在尺寸上添加一个唯一性验证如何，范围是产品ID？谢谢您的帮助，@Douglas。我试过了，但似乎都不起作用。问题似乎是，通过在尺寸模型中设置范围，所有尺寸都会显示出来，而不管产品是什么。为了解决这个问题，我在产品模型中创建了一个方法，该方法复制了DouglasThanks@Douglas建议的范围功能，这听起来是两个方法中比较好的一个。但是，当我将“大”的库存减少到0并查看下拉列表时，它会显示所有大小，包括“大”，但也会显示“小”和“中”，即“小”“中”“大”“小”“中”。有什么想法吗？谢谢，我认为这里的问题是，在我的尺码表中，我有其他尺码为“小”、“中”和“大”的产品，因此它也会在下拉列表中显示这些产品。不确定这里的解决方案是什么？如果您使用@product.size.in_库存，则应该只使用与该产品相关的尺寸。如果出现多个，则每个产品必须有多个相同的尺寸。在尺寸上添加一个唯一性验证如何，范围是产品ID？谢谢您的帮助，@Douglas。我试过了，但似乎都不起作用。问题似乎是，通过在尺寸模型中设置范围，所有尺寸都会显示出来，而不管产品是什么。为了解决这个问题，我在产品模型中创建了一个方法，该方法复制了DouglasThanks@Rudolf建议的范围功能。在我去查看我的篮框之前，这一切都如期进行。问题是，

：size

作为字符串而不是控制器期望的大小id发送。将

：size

更改为

：id

可以解决此问题，但下拉列表显示的是id，而不是人类可读的字符串。试图找出解决办法？？啊，现在我明白了！我调整了答案，见上文。谢谢@Rudolf，我想我已经试过了，但显然没有！那么，这就是解决方案？如果你接受它作为正确的答案，我将包括道格拉斯的建议，并写它作为一个范围！谢谢你，鲁道夫。在我去查看我的篮框之前，这一切都如期进行。问题在于

：大小