From: Max Muermann <ruby@...>
Date: 2006-08-29T07:13:13+09:00
Subject: Re: ActiveRecord, has_many and _count ...

I think you want the Rails mailing list...

Max

On 8/29/06, �ric DUMINIL <eric.duminil@gmail.com> wrote:
> Hi everybody!
>
> Here are trunks of models from a little rails app I'm developing:
>
> ###########################
> class Country < ActiveRecord::Base
>   has_many :companies
> ........
>
> ###########################
> class Category < ActiveRecord::Base
>   has_many :companies
> ........
>
> ###########################
> class Company < ActiveRecord::Base
>   has_many :employees , :dependent => true
>   belongs_to :country, :counter_cache => true
>   belongs_to :category, :counter_cache => true
> ........
>
> ###########################
>
> class Employee < ActiveRecord::Base
>   belongs_to :company, :counter_cache => true
> ........
>
> ###########################
>
>
> I just would like to know: The right way to create a new company by updating
> Country.find(id).companies.size is by doing
> Country.find(id).companies.create . Right?
>
> 1) But what if I'd like to keep in cache companies.size for the category in
> which the new company is put? I can't create a company simultaneously using
> two parents!
>
> 2) When I edit the properties of a company, let's say moving from Japan to
> Italy, how could I update  Japan.companies_count and Italy.companies_count?
> I tried to modify the update action of CompanieController:
>
> ###########################
>
>   def update
>     @company = Company.find(params[:id])
>     @oldcountry=@company.country
>     if @company.update_attributes(params[:company])
>       @newcountry=@company.country
>       @oldcountry.companies_count=@oldcountry.companies(:refresh).size
>       @newcountry.companies_count=@newcountry.companies(:refresh).size
>       flash[:notice] = 'Company was successfully updated.'
>       redirect_to :action => 'show', :id => @company
>     else
>       render :action => 'edit'
>     end
>   end
>
> ###########################
>
> but that did'nt work. :(
>
>
> 3) Is there a Rails' way to cache the number of Employees directly in
> Company.employees_count and Category.employees_count (i.e. through
> a "has_many_many" relation)? That would prevent iterating through every
> company of a given country/category to get its .employees_count!
>
> Thanks a lot for your attention,
>
> Have a good night,
>
> Eric
>
>
>
>
>