Rails - Aug 2006 - calculate method is gone once I use ''find''?

Could someone please explain why this works:

current_user.accounts.sum(:balance)

But not this:

current_user.accounts.find_all_by_active(true).sum(:balance)

For the latter Rails tells me sum is an undefined method. It seems like 
I lose the ActiveRecord methods when I call ''find''?

This (simpler) does not work either:

current_user.accounts.find_all.sum(:balance)

Thanks!

-- 
Posted via http://www.ruby-forum.com/.

One way:

Account.sum(:balance, :conditions => "user_id = #{current_user.id} AND
active = true")

another way:

Account.with_scope(:find => "user_id = #{current_user.id} AND active =
true") do
  Account.sum(:balance)
end


On 8/15/06, Carl Johnson <carl_ivar@yahoo.com>
wrote:
> Could someone please explain why this works:
>
> current_user.accounts.sum(:balance)
>
> But not this:
>
> current_user.accounts.find_all_by_active(true).sum(:balance)
>
> For the latter Rails tells me sum is an undefined method. It seems like
> I lose the ActiveRecord methods when I call ''find''?
>
> This (simpler) does not work either:
>
> current_user.accounts.find_all.sum(:balance)
>
> Thanks!
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Carl Johnson wrote:
> Could someone please explain why this works:
> 
> current_user.accounts.sum(:balance)
> 
> But not this:
> 
> current_user.accounts.find_all_by_active(true).sum(:balance)
> 
> For the latter Rails tells me sum is an undefined method. It seems like 
> I lose the ActiveRecord methods when I call ''find''?
> 
> This (simpler) does not work either:
> 
> current_user.accounts.find_all.sum(:balance)
In the first case, you are calling the sum method on an ActiveRecord 
object.

In the second case, you are calling sum on an array of ActiveRecord 
objects and as the error message tells you, the sum method is not 
defined for Array objects.

The missing piece that you need to know is that when the finders return 
more than one ActiveRecord the results are returned in an array of 
ActiveRecords.

You should be able to rewrite your first query

current_user.accounts.sum(:balance, :conditions => [''active ==
?'', true])

-- 

Ray

Thanks, that helps!
> You should be able to rewrite your first query
> 
> current_user.accounts.sum(:balance, :conditions => [''active ==
?'',
> true])
One question - where would be the best place for the above as far as MVC 
goes? Directly in the view or should I be setting a variable to the 
above in the controller?

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