Rails - Mar 2009 - How to do queries for 'nested :partial' structures ?

Hi there,

what''s the most resource friendly way to program the following?

In the VIEW, I need to show a ''nested :has_many'' structure
like this:

============Author1
  BookA
  ...
    ChapterX
    ...
      Page-i
      ...
  BookB
  ...
    ChapterX
    ...
      Page-i
      ...
Author2
...
============
I assume this means that:
- Author, Book, Chapter, Page must be "collections" (@authors, @books,
@chapters, @pages)
- I need to have a :partial for each collection
- Each :partial contains the next :partial (nested parent-child
structure)

My question:
- Doing (for example) the query for @books directly within the
''author''
:partial (and so on) would be stupid, wouldn''t it...
- So how do I need to write the database queries in the controller (in
the most efficient way) for such a case?
- How would this look like in the view (how to access the values)? (for
example in any child :partial)

Thank you very much for your help!
Tom
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On Mar 11, 2009, at 8:05 PM, Tom Ha wrote:
>
> Hi there,
>
> what''s the most resource friendly way to program the following?
>
> In the VIEW, I need to show a ''nested :has_many''
structure like this:
>
> ============> Author1
>  BookA
>  ...
>    ChapterX
>    ...
>      Page-i
>      ...
>  BookB
>  ...
>    ChapterX
>    ...
>      Page-i
>      ...
> Author2
> ...
> ============>
> I assume this means that:
> - Author, Book, Chapter, Page must be "collections" (@authors,
@books,
> @chapters, @pages)
> - I need to have a :partial for each collection
> - Each :partial contains the next :partial (nested parent-child
> structure)
>
> My question:
> - Doing (for example) the query for @books directly within the  
> ''author''
> :partial (and so on) would be stupid, wouldn''t it...
> - So how do I need to write the database queries in the controller (in
> the most efficient way) for such a case?
@authors = Author.find(:all, :include => { :books => { :chapters  
=> :pages }})

Of course, that''s going to instantiate all the authors, books,  
chapters, and pages into objects in your program...
>
> - How would this look like in the view (how to access the values)?  
> (for
> example in any child :partial)
>
> Thank you very much for your help!
> Tom
> -- 

In your main view,

<%= render :partial => ''author'', :collection =>
@authors %>

In the _author.html.erb

<%= render :partial => ''book'', :collection =>
author.books %>

etc.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org



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Really cool! Thanks a lot, Rob!
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