Rails - Apr 2009 - updating parent resource whenever child is updated

I have nested resources as follows: ''albums has_many photos''.
Whenever someone edits photos, I would like update time stamp on albums.
I tried to do this like:
@photos.albums.updated_by = @currentusername
@photos.albums.save

But, this is not updating albums. I don''t see anything happening in the
database log or mongrel log.

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

I think the new functionality in edge rails will do what you want:

http://afreshcup.com/2009/04/19/touch-your-active-record-instances/

You say:

class Photo
  belongs_to :user, :touch => true
end

This way, whenever you save or delete a photo instance, it''ll
''touch''
its parent user, and update the updated_at timestamp.

This will require you to upgrade to edge rails, though.

Looking at your attempt, though, I''m not sure this is what you want.
Are
you also using the "updated_by" attribute of the photo to save the id
of
the user that changed it?

Chris




Carlos Santana wrote:
> I have nested resources as follows: ''albums has_many
photos''.
> Whenever someone edits photos, I would like update time stamp on albums.
> I tried to do this like:
> @photos.albums.updated_by = @currentusername
> @photos.albums.save
> 
> But, this is not updating albums. I don''t see anything happening
in the
> database log or mongrel log.
> 
> -
> CS.
-- 
Posted via http://www.ruby-forum.com/.

Well, the updated_at timestamp for the album should update automatically 
to the current time whenever the album model is changed and saved, so if 
you''re trying to do that then you don''t need to use touching.

I''m confused at how your app is set up - if album has_many photos and 
photo belongs_to album, then shouldn''t your photo saving method use 
singular objects? As in:

@photo.album.updated_by = @currentusername
@photo.album.save

That is, assuming you''ve defined "updated_by" in your
migration as a
string to save the name of the current user - I think that''s what
you''re
going for.

What I would do next is put debugger right between those two lines, then 
call the save as a bang method (@photo.album.save!) and see what error 
you get (if any).

Chris



Carlos Santana wrote:
> Thanks Chris.
> I am using created_at and updated_at attributes for timestamps. For 
> getting user info. though, I have creuser and upduser attributes.
> 
> Is there any other way to do this other than upgrading it to edge rails?
> 
> Thanks,
> CS.
> 
> Chris Hanks wrote:
>> I think the new functionality in edge rails will do what you want:
>> 
>> http://afreshcup.com/2009/04/19/touch-your-active-record-instances/
>> 
>> You say:
>> 
>> class Photo
>>   belongs_to :user, :touch => true
>> end
>> 
>> This way, whenever you save or delete a photo instance, it''ll
''touch''
>> its parent user, and update the updated_at timestamp.
>> 
>> This will require you to upgrade to edge rails, though.
>> 
>> Looking at your attempt, though, I''m not sure this is what you
want. Are
>> you also using the "updated_by" attribute of the photo to
save the id of
>> the user that changed it?
>> 
>> Chris
>> 
>> 
>> 
>> 
>> Carlos Santana wrote:
>>> I have nested resources as follows: ''albums has_many
photos''.
>>> Whenever someone edits photos, I would like update time stamp on
albums.
>>> I tried to do this like:
>>> @photos.albums.updated_by = @currentusername
>>> @photos.albums.save
>>> 
>>> But, this is not updating albums. I don''t see anything
happening in the
>>> database log or mongrel log.
>>> 
>>> -
>>> CS.
-- 
Posted via http://www.ruby-forum.com/.

It uses singular objects. I am sorry I typed it wrongly over here.

I tried to debug it using console. My observation was if:
@photo.album.upduser = @currentuser is same as previous user then 
timestamps are not getting changes. However, @photo.album.save works and 
returns true.

Any clues?

Thanks,
CS.

Chris Hanks wrote:
> Well, the updated_at timestamp for the album should update automatically 
> to the current time whenever the album model is changed and saved, so if 
> you''re trying to do that then you don''t need to use
touching.
> 
> I''m confused at how your app is set up - if album has_many photos
and
> photo belongs_to album, then shouldn''t your photo saving method
use
> singular objects? As in:
> 
> @photo.album.updated_by = @currentusername
> @photo.album.save
> 
> That is, assuming you''ve defined "updated_by" in your
migration as a
> string to save the name of the current user - I think that''s what
you''re
> going for.
> 
> What I would do next is put debugger right between those two lines, then 
> call the save as a bang method (@photo.album.save!) and see what error 
> you get (if any).
> 
> Chris
> 
-- 
Posted via http://www.ruby-forum.com/.

Because the upduser is the same, it doesn''t think that the object has
really changed, so doesn''t update the timestamps.

We had a similar problem where we needed to update the timestamps on the root
object of a tree whenever anything in the tree changed. I ended up implementing
a touch method on the object, and called that in a before_save hook.


  def touch
    orig_title = self.title
    self.title = '' ''
    self.title = orig_title
    self.save
  end

  def after_save_hook
    root.touch
    true
  end

the edge rails code looks much nicer, but it will be a while before we can move
to newer rails.

Simon

On Wed, 29 Apr 2009 10:23:03 +0800, Carlos Santana
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
> It uses singular objects. I am sorry I typed it wrongly over here.
>
> I tried to debug it using console. My observation was if:
> @photo.album.upduser = @currentuser is same as previous user then
> timestamps are not getting changes. However, @photo.album.save works and
> returns true.
>
> Any clues?
>
> Thanks,
> CS.
>
> Chris Hanks wrote:
>> Well, the updated_at timestamp for the album should update
automatically
>> to the current time whenever the album model is changed and saved, so
if
>> you''re trying to do that then you don''t need to use
touching.
>>
>> I''m confused at how your app is set up - if album has_many
photos and
>> photo belongs_to album, then shouldn''t your photo saving
method use
>> singular objects? As in:
>>
>> @photo.album.updated_by = @currentusername
>> @photo.album.save
>>
>> That is, assuming you''ve defined "updated_by" in
your migration as a
>> string to save the name of the current user - I think that''s
what you''re
>> going for.
>>
>> What I would do next is put debugger right between those two lines,
then
>> call the save as a bang method (@photo.album.save!) and see what error
>> you get (if any).
>>
>> Chris
>>
>

Thats weired..
I would expect parent.save to return false then.. :(

Thanks for the help.

CS.

Simon Macneall wrote:
> Because the upduser is the same, it doesn''t think that the object
has
> really changed, so doesn''t update the timestamps.
> 
> We had a similar problem where we needed to update the timestamps on the 
> root object of a tree whenever anything in the tree changed. I ended up 
> implementing a touch method on the object, and called that in a 
> before_save hook.
> 
> 
>   def touch
>     orig_title = self.title
>     self.title = '' ''
>     self.title = orig_title
>     self.save
>   end
> 
>   def after_save_hook
>     root.touch
>     true
>   end
> 
> the edge rails code looks much nicer, but it will be a while before we 
> can move to newer rails.
> 
> Simon
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