Rails - Jan 2009 - [Help] With no persistence, instances share among actions failed.

Hi!

My problem instance''s properties failed to share among the actions.
e.g. In action ''collect'', I created an "CD" instance
with some
"Album"s as its properties
using one-many relationship provided by rails API.
Before saving to the db, I just pass the ''CD'' instance to
action
''show'', using @instance_var.
But I can''t get properties information using
''cd.albums'', it alway
return an empty array.

The reason why the objects do not get persisted is that modification
of objects is necessary.

Why can''t I navigate through the relation and How can I pass around
the instance without?
--------------------------------------------------------------------

# model
class Cd < ActiveRecord::Base
        has_many :albums
end

class Album < ActiveRecord::Base
        belongs_to :cd
end

# in action "collect"
@cd = Cd.new
Dir.chdir("/media/cdrom")
        Dir.foreach(Dir.pwd) do | dir |
           logger.debug "found directory : [#{dir}]"
           if dir != "." && dir != ".."
                # collect album inf
                raw_info = dir
                @al = Album.new
                @al.name = dir.to_s
                @al.cd = @cd
                logger.debug "Checking album[#{@al.name}]''s
belonging
[#{@al.cd.volumn_name}]"
                logger.debug "Find album folder [#{dir}], thus cd
contains [#{@cd.albums}]"
	   end
	end
end

logging:
Processing MusicInventoryController#collect (for 127.0.0.1 at
2009-01-08 14:13:14) [GET]
found directory : [.]
found directory : [..]
found directory : [20090101]
Checking album[20090101]''s belonging [test]
Find album folder [20090101], thus cd contains []
Rendering music_inventory/show



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On Jan 8, 6:47 am, "J.C. Zhu"
<realal...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hi!
>
> My problem instance''s properties failed to share among the
actions.
> e.g. In action ''collect'', I created an "CD"
instance with some
> "Album"s as its properties
> using one-many relationship provided by rails API.
> Before saving to the db, I just pass the ''CD'' instance to
action
> ''show'', using @instance_var.
> But I can''t get properties information using
''cd.albums'', it alway
> return an empty array.
>
You never save the @al object, so it''s not going to magically appear
in @cd.albums. If you want to add an unsaved object to @cd.albums you
can do
@cd.albums.create ...

Fred


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