Rails - Mar 2006 - Newbie: ''find'' across multiple relationships

For security purposes, I often want to find objects that are
''visible''.

e.g.

class Person < ActiveRecord::Base
  has_many :x
end

...

@person.x.find(params[:id]) as opposed to X.find([params[:id]). Simple
enough for me.

My question:

Say we have -

class Person < ActiveRecord::Base
  has_many :x, :class_name ''Z'', ....
  has_many :y, :class_name ''Z'', ...
end

In other words, two different associations for the same type of model.
Maybe the second collection is a habtm, etc.

What is the best technique for doing a find on the union of those
collections? I can think of a half dozen ways, but none of them seem
''idiomatic''.

Thanks

-- 
Posted via http://www.ruby-forum.com/.

Am Donnerstag, den 23.03.2006, 02:07 +0100 schrieb John
Smith:
> For security purposes, I often want to find objects that are
''visible''.
> 
> e.g.
> 
> class Person < ActiveRecord::Base
>   has_many :x
> end
> 
> ...
> 
> @person.x.find(params[:id]) as opposed to X.find([params[:id]). Simple
> enough for me.
> 
> My question:
> 
> Say we have -
> 
> class Person < ActiveRecord::Base
>   has_many :x, :class_name ''Z'', ....
>   has_many :y, :class_name ''Z'', ...
> end
> 
> In other words, two different associations for the same type of model.
> Maybe the second collection is a habtm, etc.
> 
> What is the best technique for doing a find on the union of those
> collections? I can think of a half dozen ways, but none of them seem
> ''idiomatic''.
What about:

@person.x.find(params[:id]) || @person.y.find(params[:id])


-- 
Norman Timmler

http://blog.inlet-media.de

Norman Timmler wrote:
> Am Donnerstag, den 23.03.2006, 02:07 +0100 schrieb John Smith:
>> @person.x.find(params[:id]) as opposed to X.find([params[:id]). Simple
>> 
>> In other words, two different associations for the same type of model.
>> Maybe the second collection is a habtm, etc.
>> 
>> What is the best technique for doing a find on the union of those
>> collections? I can think of a half dozen ways, but none of them seem
>> ''idiomatic''.
> 
> What about:
> 
> @person.x.find(params[:id]) || @person.y.find(params[:id])
> 
> 
> --
> Norman Timmler
> 
> http://blog.inlet-media.de

Doesn''t find throw RecordNotFound (as opposed to returning nil or an 
empty collection)?.

In any case, I don''t think it would produce the desired effect as I
want
a collection that contains all the results from both associations in the 
case where both have results.

Right now I''ve just defined a method in the model that uses a custom 
conditional to find to OR the different possibilities. Maybe that''s a 
reasonable approach.





-- 
Posted via http://www.ruby-forum.com/.

Am Donnerstag, den 23.03.2006, 16:42 +0100 schrieb John
Smith:
> Norman Timmler wrote:
> > Am Donnerstag, den 23.03.2006, 02:07 +0100 schrieb John Smith:
> >> @person.x.find(params[:id]) as opposed to X.find([params[:id]).
Simple
> >> 
> >> In other words, two different associations for the same type of
model.
> >> Maybe the second collection is a habtm, etc.
> >> 
> >> What is the best technique for doing a find on the union of those
> >> collections? I can think of a half dozen ways, but none of them
seem
> >> ''idiomatic''.
> > 
> > What about:
> > 
> > @person.x.find(params[:id]) || @person.y.find(params[:id])
> Doesn''t find throw RecordNotFound (as opposed to returning nil or
an
> empty collection)?.
> 
> In any case, I don''t think it would produce the desired effect as
I want
> a collection that contains all the results from both associations in the 
> case where both have results.
You are right:

(@person.x.find(params[:id]) rescue nil) || @person.y.find(params[:id])

-- 
Norman Timmler

http://blog.inlet-media.de