Hello world... I have an interesting issue that the online docs aren't helping me with. In my app I have 4 models Item < ActiveRecord Deal < Item Product < Item Category < ActiveRecord Item has_and_belongs_to_many :categories... On each category record I'd like to maintain a product_count and deal_count to increase performance. This doesn't appear possible with the current "counter_cache" declaration. Anyone have ideas on how to approach this? In the past I've just run an hourly cron task to calculate & update all records of this type, but I feel this probably isn't the most efficient (or accurate). Ideas, comments?
on 2006-05-23 00:11
on 2006-05-23 02:31
On 5/22/06, subimage interactive <firstname.lastname@example.org> wrote: > On each category record I'd like to maintain a product_count and deal_count > to increase performance. This doesn't appear possible with the current > "counter_cache" declaration. > > Anyone have ideas on how to approach this? I don't know how heavy the updating or saving of the model data is, but you can always use callbacks to do the counts before saving... class Category < ActiveRecord::Base def before_save self.products_count = Product.count('id', :conditions => ["category_id=?",self.id]) self.deals_count = Deal.count('id', :conditions => ["category_id=?",self.id]) end end -- Sincerely, Frodo L.
on 2006-05-23 03:23
That's not even where the updating will happen. This would work in a lazy fashion, but I was just looking to see if I overlooked anything in AR that would do it for me. Currently I have a cron script that runs (just to make sure the numbers are right), plus my own add/remove category methods on Item that update the counts manually.
on 2006-05-23 11:20
Figured out a nice way to handle this for those of you who search it out later. There are 2 methods you can call on HABTM relationships "after_add" and "after_remove". I'm calling update_counts from there.