Rails - Dec 2005 - How do you detect if ActiveRecord ''update'' fails?

So I''m updating multiple model objects in one go with something like  
this in my controller:
=>	Photo.update(params[:photo].keys, params[:photo].values)

When the update fails due to validation errors, how do I detect it?  
The Rails API says:
"If the save fails under validations, the unsaved object is still  
returned."
So I can''t simply do this:
  =>	if Photo.update(params[:photo].keys, params[:photo].values)

Any suggestions?

_______________________________________________
Rails mailing list
Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
http://lists.rubyonrails.org/mailman/listinfo/rails

On 12/27/05, Justin Rhoades
<justin.rhoades-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> So I''m updating multiple model objects in one go with something
like this in
> my controller:
> => Photo.update(params[:photo].keys, params[:photo].values)
>
> When the update fails due to validation errors, how do I detect it? The
> Rails API says:
> "If the save fails under validations, the unsaved object is still
returned."
> So I can''t simply do this:
>  => if Photo.update(params[:photo].keys, params[:photo].values)
>
> Any suggestions?
@photo = Photo.find(params[:id])
if @photo.update_attributes(params[:photo])...

--
rick
http://techno-weenie.net

"@photo = Photo.find(params[:id])
if @photo.update_attributes(params[:photo])..."

At first glance, that seems great for updating ONE model instance.  
But I''m updating multiple objects. Are you suggesting that I should  
loop through each of the key-values and check that way, like so:

for  params[:photo].each do |id|
	@photo= Photo.find(id)
	if @photo.update_attributes(params[:photo].values[id])
		...
	end
end

? (Sorry for the poor code, but you know what I''m getting at, right?)




On Dec 27, 2005, at 10:17 | Dec 27, Rick Olson wrote:
> On 12/27/05, Justin Rhoades
<justin.rhoades-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> So I''m updating multiple model objects in one go with
something
>> like this in
>> my controller:
>> => Photo.update(params[:photo].keys, params[:photo].values)
>>
>> When the update fails due to validation errors, how do I detect  
>> it? The
>> Rails API says:
>> "If the save fails under validations, the unsaved object is still
>> returned."
>> So I can''t simply do this:
>>  => if Photo.update(params[:photo].keys, params[:photo].values)
>>
>> Any suggestions?
>
> @photo = Photo.find(params[:id])
> if @photo.update_attributes(params[:photo])...
>
> --
> rick
> http://techno-weenie.net
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

On 12/27/05, Justin Rhoades
<justin.rhoades-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
>
> "@photo = Photo.find(params[:id])
> if @photo.update_attributes(params[:photo])..."
>
> At first glance, that seems great for updating ONE model instance.
> But I''m updating multiple objects. Are you suggesting that I
should
> loop through each of the key-values and check that way, like so:
>
> for  params[:photo].each do |id|
>         @photo= Photo.find(id)
>         if @photo.update_attributes(params[:photo].values[id])
>                 ...
>         end
> end
>
> ? (Sorry for the poor code, but you know what I''m getting at,
right?)
Well, I seem to be getting your requirements in pieces, so it''s hard
figuring out how to phrase this :)

For instance, do you want the whole save operation to stop?  If so,
use save! and a transaction  I''m not sure how you have your hash
structured, but I''m guessing it''s like:

params[:photo] = {
 1 => { photo_params },
 2 => { photo_params }...
}

def foo
  Photo.transaction do
    params[:photo].each do |id, photo_attributes|
      @photo = Photo.find(id)
      @photo.attributes = photo_attributes
      @photo.save!
    end
  end
rescue
  error handling...
end

When save! fails due to a validation error, it raises an exception and
rolls back the transaction.

Oh, the simple solution is probably to just loop through the photos
after calling Photo.update and checking photos[i].errors.empty?

--
rick
http://techno-weenie.net

Sweet, thanks Rick. That certainly answers my question and confirms  
that I gotta go about it the ''hard'' way. Wouldn''t it
be nice if
ActiveRecord ''update'' returned some kind of indication of
errors if
any of its attempted ''saves'' fail? (Nice bit about that  
ActiveRecord.errors.empty?, very useful.) Ah well...


On Dec 27, 2005, at 11:59 | Dec 27, Rick Olson wrote:
> On 12/27/05, Justin Rhoades
<justin.rhoades-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>
>> "@photo = Photo.find(params[:id])
>> if @photo.update_attributes(params[:photo])..."
>>
>> At first glance, that seems great for updating ONE model instance.
>> But I''m updating multiple objects. Are you suggesting that I
should
>> loop through each of the key-values and check that way, like so:
>>
>> for  params[:photo].each do |id|
>>         @photo= Photo.find(id)
>>         if @photo.update_attributes(params[:photo].values[id])
>>                 ...
>>         end
>> end
>>
>> ? (Sorry for the poor code, but you know what I''m getting at,
right?)
>
> Well, I seem to be getting your requirements in pieces, so it''s
hard
> figuring out how to phrase this :)
>
> For instance, do you want the whole save operation to stop?  If so,
> use save! and a transaction  I''m not sure how you have your hash
> structured, but I''m guessing it''s like:
>
> params[:photo] = {
>  1 => { photo_params },
>  2 => { photo_params }...
> }
>
> def foo
>   Photo.transaction do
>     params[:photo].each do |id, photo_attributes|
>       @photo = Photo.find(id)
>       @photo.attributes = photo_attributes
>       @photo.save!
>     end
>   end
> rescue
>   error handling...
> end
>
> When save! fails due to a validation error, it raises an exception and
> rolls back the transaction.
>
> Oh, the simple solution is probably to just loop through the photos
> after calling Photo.update and checking photos[i].errors.empty?
>
> --
> rick
> http://techno-weenie.net
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails