Rails - Dec 2006 - Am I hitting the database twice?

Controller:
@books.collect { |book| book.authors }


View:
<td>
  <% for author in book.authors %>
    <%= h author.name %>
  <% end %>
</td>

When I comment out the controller line I get the same result.  So should
I let the view hit the database on its own or is there some benefit to
doing it in the controller?  Code in the view cannot be refactored in
either situation.

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Taylor Strait wrote:
> Controller:
> @books.collect { |book| book.authors }
> 
> 
> View:
> <td>
>   <% for author in book.authors %>
>     <%= h author.name %>
>   <% end %>
> </td>
> 
> When I comment out the controller line I get the same result.  So should
> I let the view hit the database on its own or is there some benefit to
> doing it in the controller?  Code in the view cannot be refactored in
> either situation.
Not sure I understand what you are trying to do but if you wanna list 
authors that belongs_to book

in controlloer

def show
  @book = Book.find(params[:id])
end

in view
<% for author in @book.authors %>
   <%= h author.name %>
<% end %>


www.sylow.net

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Hi --

On Sun, 3 Dec 2006, Taylor Strait wrote:
>
> Controller:
> @books.collect { |book| book.authors }
>
>
> View:
> <td>
>  <% for author in book.authors %>
>    <%= h author.name %>
>  <% end %>
> </td>
>
> When I comment out the controller line I get the same result.  So should
> I let the view hit the database on its own or is there some benefit to
> doing it in the controller?  Code in the view cannot be refactored in
> either situation.
The controller line appears to discard its result, so I''m not
surprised that commenting it out makes no difference :-)

Assuming that there''s a line like this in the controller:

   @books = Book.find(:all)

and like this in the view:

   <% @books each do |book| %>   # or an equivalent for loop

you could change the controller line to:

   @books = Book.find(:all, :include => "authors")

which would pre-load all the author records into the @books collection
and save some database hits later on.


David

-- 
                   David A. Black |
dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org
Author of "Ruby for Rails"   [1] | Ruby/Rails training &
consultancy [3]
DABlog (DAB''s Weblog)        [2] | Co-director, Ruby Central, Inc.  
[4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org

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