Has anyone come across documentation on how to execute an
update_by_sql function on an ActiveRecord object?
This would be similar to X.find_by_sql.
Any help would be greatly appreciated!
Why not? 
I have a situation where I need to update a custom counter
periodically and don't want to create a ton of overhead accomplishing
this when I can do it with a simple update statement:
update categories set categories.product_count = (select count(*) from
categories_products where category_id = categories.id);
The goal is to have a product_count on the categories table. However,
the product has_and_belongs_to_many :categories
So the traditional magic column doesn't apply... unless I am missing
the obvious here.
AR::Base#connection.execute (i don't remember if it's a class or
instance method, but search for it
http://nick.recoil.org/2006/8/12/searching-for-a-rails-delete_by_sql-method
gene -
That did the trick! Thanks a lot!
Here is an overview of what I ended up with, in case anyone else
stumbles here...
class Category < ActiveRecord::Base
has_and_belongs_to_many :products, :order=>'products.name'
has_many :categories_products
validates_uniqueness_of :name
def self.update_product_counts
sql = "update categories set categories.product_count = (select
count(*) from categories_products where category_id = categories.id);"
connection.update(sql)
end
end
peri wrote:
I have a situation where I need to update a custom counter
periodically and don't want to create a ton of overhead accomplishing
this when I can do it with a simple update statement:update categories set categories.product_count = (select count(*) from
categories_products where category_id = categories.id);The goal is to have a product_count on the categories table. However,
the product has_and_belongs_to_many :categories
May be you move to has_many :througth and magic columns will be back
Actually it's
ActiveRecord::Base.connection.update(sql)
It's probably better to get the connection from the AR class whose
instance you are updating.
correct. Never a good sign when one of the top google hits is a trac
saying there's no docs for this method:
