Rails - Mar 2007 - Cannot change attribute with self[:attribute]= or write_attribute(:attribute, value)

Hey,

I have a model called Vocab with an integer variable named box. I
defined a method named promote which increases box by one:

def promote
  self[:box] += 1
end

I put a link in the list.rhtml view created by scaffold

...
<% for vocab in @vocabs %>
...
<td><%= link_to ''Promote'', :action =>
''promote'', :id => vocab %></td>
...

and created a promote message in the controller, which passes it on to
the model

def promote
  @vocab = Vocab.find(params[:id])
  @vocab.promote;
  redirect_to :action => ''list''
end

However, this isn''t working; the box variable stays the same. Changing
the model''s method to

def promote
  value_before = self[:box]
  self[:box] += 1
  value_after = self[:box]
  logger.error "Oops! First, box was #{value_before} and now it''s
#{value_after}."
end

produces this in development.log:

Oops! First, box was 4 and now it''s 5.

So the variable box does change, but the database entry probably
hasn''t been updated. I also tried write_attribute, but no luck. What
am I doing wrong?

Thanks.


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

When promote is called, Vocab.box will be incremented, right?  If you 
don''t save the record, the new value of Vocab.box will be gone the next
time you tried to access the Vocab model.

In the other word, you would need self.save! in the promote method.

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

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

ah yes, that did the trick. Thanks!

I also realized that self[:box] is unnecessary, since I''m not
overwriting any readers or writers.

On Apr 1, 4:27 am, Wai Tsang
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> When promote is called, Vocab.box will be incremented, right?  If you
> don''t save the record, the new value of Vocab.box will be gone the
next
> time you tried to access the Vocab model.
>
> In the other word, you would need self.save! in the promote method.
>
> --
> Posted viahttp://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---