Rails - Feb 2006 - belongs_to, has_one, has_many question (again?)

Hi All,

Probably this has been asked numerous times, I apologize already!
Can somebody point me to a good tutorial on how Rails works with  
relations?

I know about database design and normalization, I also know about  
programming in general (and OOP for that matter).

Only thing I can say is that I''m following the "Four days on
Rails"
tutorial by John McCreesh.
He writes on Items and Notes (for his Todo example).

The items table has a key to the note_id. However (and this in  
particular I''m trying to understand), the Models which accompany the  
tables (item & note) are like:

class Item                class Note
belongs_to: note          # nothing here really
.                         .
.                         .
end                       end

It only struck me that I have the feeling that "it" (belongs_to)  
should be the other way around.
I''m actually looking for some page which spills out the relations or  
associations within Rails, like:

1:1 relation: has_one, belongs_to in such and such way
1:many relation has_many, belongs_to in such and such way
many:many relation: already has a tutorial of it''s own! (http:// 
jrhicks.net/Projects/rails/has_many_and_belongs_to_many.pdf)

Thanks,
Tom

On Feb 20, 2006, at 2:49 PM, Tom de Grunt wrote:
> Hi All,
>
> Probably this has been asked numerous times, I apologize already!
> Can somebody point me to a good tutorial on how Rails works with  
> relations?
>
> I know about database design and normalization, I also know about  
> programming in general (and OOP for that matter).
>
> Only thing I can say is that I''m following the "Four days on
Rails"
> tutorial by John McCreesh.
> He writes on Items and Notes (for his Todo example).
>
> The items table has a key to the note_id. However (and this in  
> particular I''m trying to understand), the Models which accompany  
> the tables (item & note) are like:
>
> class Item                class Note
> belongs_to: note          # nothing here really
> .                         .
> .                         .
> end                       end
>
> It only struck me that I have the feeling that "it" (belongs_to)
> should be the other way around.
> I''m actually looking for some page which spills out the relations
> or associations within Rails, like:
>
> 1:1 relation: has_one, belongs_to in such and such way
> 1:many relation has_many, belongs_to in such and such way
> many:many relation: already has a tutorial of it''s own! (http:// 
> jrhicks.net/Projects/rails/has_many_and_belongs_to_many.pdf)
>
> Thanks,
> Tom

Tom-

	Here is a link with a lot of info:

http://ar.rubyonrails.com/classes/ActiveRecord/Associations/ 
ClassMethods.html

	And you have it correct already, the belongs_to is a bit confusing.  
It helps to think about it this way, instead of belongs to think  
referrs_to or has_fkey_that_refers_to . The model that belongs_to  
another model is the one that has the foriegn key so since item has a  
note_id columns item belongs_to Note or Item refers_to Note.

Cheers-
-Ezra Zygmuntowicz
WebMaster
Yakima Herald-Republic Newspaper
ezra@yakima-herald.com
509-577-7732