Forum: Ruby on Rails Missing documentation for find_in_collection? Trying to dril

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Ken C. (Guest)
on 2006-05-05 09:53
(Received via mailing list)
I've been reading up in ActiveRecord::Associations and playing around
with my app via the console and found some interesting methods via
the code completion of IRB, but I have no idea how to use them and
can only find one hint in the API

It mentions here in the has many associations that if you use the
finder_sql that you would loose the find_in_collection. What are
these and the find_all_in_collection methods I am finding. For
example the simple models i am using is a 4-tier has_many structure
like this:

class User < ActiveRecord::Base
   has_many      :foos,

class Foo < ActiveRecord::Base
   belongs_to    :user
   has_many      :bars,

class Bar < ActiveRecord::Base
   belongs_to    :foo
   has_many      :mistakes,

class Mistake < ActiveRecord::Base
   belongs_to    :bar

So while in IRB via the console of my app, I can do this and see all
the following options via command completion on the next step.

 >> @user = User.find(1)
=> #<User:0x26eb9cc @attributes={...
 >> @user.find
@user.find_mapped_obj_class           @user.find_tag
@user.find_mapped_soap_class          @user.find_target
@user.find_name                       @user.find_user_object
 >> @user.find_in_foos(1)
=> #<Foo:0x26a0008 @attributes={

It's really crazy, I can use that method @user.find_in_foos(1) and
get an object that belongs to the user and once that is done, it
opens up more find commands (specifically find_all_in_bars and
find_in_bars) to the next layer in my tier. So now I want to try and
find an associated object to the user by using the new methods. But
it fails if the association is more than 1 deep. So for example...

 >> @user.find_in_bars(1)
NoMethodError: LOG:  duration: 468.984 ms  statement: SELECT * FROM
columns WHERE (foos.user_id = 1)  ORDER BY position
undefined method `find_in_bars' for #<User:0x26eb9cc>
         from /opt/local/lib/ruby/gems/1.8/gems/activerecord-1.14.2/
lib/active_record/base.rb:1792:in `method_missing'
         from (irb):3

These methods look like they would be fun to use. Ultimately I just
want to find an object thru an association starting at the top. Any
feedback advise?

  - Ken
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