[英]Rails meta_search gem: sort by count of an associated model
I'm using meta_search to sort columns in a table. 我正在使用meta_search对表中的列进行排序。 One of my table columns is a count of the associated records for a particular model.
我的一个表列是特定模型的相关记录的计数。
Basically it's this: 基本上是这样的:
class Shop < ActiveRecord::Base
has_many :inventory_records
def current_inventory_count
inventory_records.where(:current => true).count
end
end
class InventoryRecord < ActiveRecord::Base
belongs_to :shop
#has a "current" boolean on this which I want to filter by as well
end
In my Shop#index view I have a table that lists out the current_inventory_count for each Shop. 在我的Shop #index视图中,我有一个表格列出了每个商店的current_inventory_count。 Is there anyway to use meta_search to order the shops by this count?
无论如何使用meta_search按此计数订购商店?
I can't use my current_inventory_count method as meta_search can only use custom methods that return an ActiveRecord::Relation type. 我无法使用current_inventory_count方法,因为meta_search只能使用返回ActiveRecord :: Relation类型的自定义方法。
The only way I can think about doing this is to do some custom SQL which includes the count in a "virtual" column and do the sorting by this column. 我能想到这样做的唯一方法是做一些自定义SQL,其中包括“虚拟”列中的计数,并按此列进行排序。 I'm not sure if that's even possible.
我不确定这是否可能。
Any Ideas? 有任何想法吗?
I'm using Rails 3.0.3 and the latest meta_search. 我正在使用Rails 3.0.3和最新的meta_search。
To add extra columns to a result set... 要向结果集添加额外的列...
In Shop.rb .. 在Shop.rb ..
scope :add_count_col, joins(:inventory_records).where(:current=>true).select("shops.*, count(DISTINCT inventory_records.id) as numirecs").group('shops.id')
scope :sort_by_numirecs_asc, order("numirecs ASC")
scope :sort_by_numirecs_desc, order("numirecs DESC")
In shops_controller.rb index method 在shops_controller.rb索引方法中
@search = Shop.add_count_col.search(params[:search])
#etc.
In index.html.erb 在index.html.erb中
<%= sort_link @search, :numirecs, "Inventory Records" %>
Found the sort_by__asc reference here: http://metautonomo.us/2010/11/21/metasearch-metawhere-and-rails-3-0-3/ 在这里找到sort_by__asc参考: http ://metautonomo.us/2010/11/21/metasearch-metawhere-and-rails-3-0-3/
Rails has a built-in solution for this called counter_cache Rails有一个内置的解决方案,称为counter_cache
Create a table column named "inventory_records_count" on your shops table. 在商店表上创建名为“inventory_records_count”的表列。
class Shop < ActiveRecord::Base
has_many :inventory_records, :counter_cache => true
end
http://asciicasts.com/episodes/23-counter-cache-column http://asciicasts.com/episodes/23-counter-cache-column
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