Rails - Apr 2007 - [PLUGIN] count_from_query - easily convert finder queries into count queries

count_from_query gives you the ability to generate a COUNT query from
a standard Rails find.

For example, if you have the query

User.find :all

it would be trivial to get a count:

User.count

however, if you have a more specific finder method, such as

class Company < ActiveRecord::Base
def complete_videos
Video.find :all, :conditions => "company_id=#{id} AND
status=''complete''", :order => "created_at
DESC"
end
end

Getting the count isn''t quite as easy. You could just call #size on
the returned array, but it''s wasteful if you don''t actually
need the
records. You could write a complete_videos_count method, but it
doesn''t feel very DRY to have two methods every time you want to do a
count query as well.

With count_from_query, it''s cake

videos_count = ActiveRecord::Base.count_from_query {
my_company.complete_videos }

You can wrap any AR find call in count_from_query to have it be
converted into a count query.

Association proxies work the same way. We could change the
complete_videos definition to be

class Company < ActiveRecord::Base
def complete_videos
videos.find :all, :conditions =>
"status=''complete''", :order =>
"created_at DESC"
end
end

and get the same result.

ruby script/plugin install svn://evang.eli.st/public/plugins/count_from_query

Released under the MIT License

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Pat Maddox wrote:
> count_from_query gives you the ability to generate a COUNT query from
> a standard Rails find.
>
> For example, if you have the query
>
> User.find :all
>
> it would be trivial to get a count:
>
> User.count
>
> however, if you have a more specific finder method, such as
>
> class Company < ActiveRecord::Base
> def complete_videos
> Video.find :all, :conditions => "company_id=#{id} AND
> status=''complete''", :order => "created_at
DESC"
> end
> end
>
> Getting the count isn''t quite as easy. You could just call #size
on
> the returned array, but it''s wasteful if you don''t
actually need the
> records. You could write a complete_videos_count method, but it
> doesn''t feel very DRY to have two methods every time you want to
do a
> count query as well.
>
> With count_from_query, it''s cake
>
> videos_count = ActiveRecord::Base.count_from_query {
> my_company.complete_videos }
>
> You can wrap any AR find call in count_from_query to have it be
> converted into a count query.
>
> Association proxies work the same way. We could change the
> complete_videos definition to be
>
> class Company < ActiveRecord::Base
> def complete_videos
> videos.find :all, :conditions =>
"status=''complete''", :order =>
> "created_at DESC"
> end
> end
>
> and get the same result.
>
> ruby script/plugin install
svn://evang.eli.st/public/plugins/count_from_query
>
> Released under the MIT License
>
> >
>
>   
Congrats! This is fantastic!

Gustav Paul

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