Forum: Ruby on Rails Structuring a has_many query

I have the following models:

Category:
has_many :sub_categories

Sub_Category:

belongs_to :category
has_many :posts

Post:
belongs_to :sub_category

I'm trying to build a page that will list Categories with Pjax tabs and
then each Category tab will list all it's Sub-Categories in widgets with 
5
posts in each widget.

I have an idea of how to loop through the data once I have it but I'm
having trouble structuring the query. Thanks for any help.

@category.sub_categories.each do |sub_cat|
  sub_cat.posts.each_slice(5) do |posts|
    #here you create a widget, posts have at most 5 elements thanks to 
each_slice method
    posts.each do |post|
      #do something with each post
    end
  endend

On 4 March 2013 15:35, Anthony DeFreitas <anthony@caribbeanhotels.com> 
wrote:
> Post:
>   sub_cat.posts.each_slice(5) do |posts|
>     #here you create a widget, posts have at most 5 elements thanks to
> each_slice method
>     posts.each do |post|
>       #do something with each post
>     end
>   end
> end

It is not clear to me what question you are trying to ask here.

Colin

My question is how do I structure a query that will return all the
categories with the related sub-categories and the related posts.

On 5 March 2013 01:43, Anthony DeFreitas <anthony@caribbeanhotels.com> 
wrote:
> My question is how do I structure a query that will return all the
> categories with the related sub-categories and the related posts.

If you just get all the relevent categories in @categories then for
each category accessed via something like
@categories.each do |category|
then you can use category.sub_categories and then for each of those
the posts in exactly the way suggested in your original code.  There
is no need to do anything special in the query, just fetch the
relevant categories.

By the way could you not top post please, it makes it difficult to
follow the thread.  Insert you reply at appropriate points in the
previous message.  Thanks.

Colin

On Tue, Mar 5, 2013 at 2:56 PM, Colin Law <clanlaw@googlemail.com> 
wrote:

> is no need to do anything special in the query, just fetch the
> >>
> >> > has_many :posts
> >> >
> >> > I have an idea of how to loop through the data once I have it but I'm
> >> > having
> >> > trouble structuring the query. Thanks for any help.
> >> >
>

Do you mean to say you've got the view code but don't know what should 
go
in the controller?

You dont need to structure the query to the db. you get all categories,
subcategories and posts with @categories = Category.all (or something 
like
Category.where(:xy => z)

You can iterate over the @categories like this:

@categories.each do |category|
   # Do stuff for your category iteration here
   category.sub_categories.each do |sub|
      # Do stuff of sub category here
      sub.posts.each_slice(5) do |slice|
         # Slice stuff here (each 5 posts do something, like a div or
something.)
         slice.each do |post|
            # do single post stuff here
         end
      end
   end
end


Am Dienstag, 5. Mrz 2013 02:43:50 UTC+1 schrieb Anthony DeFreitas: