Rails - May 2006 - ActiveRecord after save new and old values

I want to write a function that after an ActiveRecord saves
successfully, can show me what the before and after values of a
particular column are.  Is this possible without creating a separate
object before modifying the current one?

-John

Hi John,

Have a look at callback methods and observer classes. The following is
an example of using callback methods. Have a look at the modules
ActiveRecord::Callbacks and ActiveRecord::Observer on
http://api.rubyonrails.org/ for a full description of what is possible

class Foo
  before_save :collect_before_values
  after_save : collect_after_values

  def collect_before_values
    # ...
  end

  def collect_after_values
    # ...
  end
end

Hope that helps!

cheers
Martin

On 5/18/06, John Oxley <john@yoafrica.com> wrote:
> I want to write a function that after an ActiveRecord saves
> successfully, can show me what the before and after values of a
> particular column are.  Is this possible without creating a separate
> object before modifying the current one?
>
> -John
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Doh, of course the class definition should look like

class Foo < ActiveRecord::Base
  # ...
end

cheers
Martin

On 5/18/06, Martin Gamsjaeger <gamsnjaga@gmail.com>
wrote:
> Hi John,
>
> Have a look at callback methods and observer classes. The following is
> an example of using callback methods. Have a look at the modules
> ActiveRecord::Callbacks and ActiveRecord::Observer on
> http://api.rubyonrails.org/ for a full description of what is possible
>
> class Foo
>   before_save :collect_before_values
>   after_save : collect_after_values
>
>   def collect_before_values
>     # ...
>   end
>
>   def collect_after_values
>     # ...
>   end
> end
>
> Hope that helps!
>
> cheers
> Martin
>
> On 5/18/06, John Oxley <john@yoafrica.com> wrote:
> > I want to write a function that after an ActiveRecord saves
> > successfully, can show me what the before and after values of a
> > particular column are.  Is this possible without creating a separate
> > object before modifying the current one?
> >
> > -John
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>

Thanks,

That''s exactly what I wanted.

-John

On Thu, May 18, 2006 at 07:10:30PM +0200, Martin Gamsjaeger
wrote:
> Hi John,
> 
> Have a look at callback methods and observer classes. The following is
> an example of using callback methods. Have a look at the modules
> ActiveRecord::Callbacks and ActiveRecord::Observer on
> http://api.rubyonrails.org/ for a full description of what is possible
> 
> class Foo
>  before_save :collect_before_values
>  after_save : collect_after_values
> 
>  def collect_before_values
>    # ...
>  end
> 
>  def collect_after_values
>    # ...
>  end
> end
> 
> Hope that helps!
> 
> cheers
> Martin
> 
> On 5/18/06, John Oxley <john@yoafrica.com> wrote:
> >I want to write a function that after an ActiveRecord saves
> >successfully, can show me what the before and after values of a
> >particular column are.  Is this possible without creating a separate
> >object before modifying the current one?
> >
> >-John
> >_______________________________________________
> >Rails mailing list
> >Rails@lists.rubyonrails.org
> >http://lists.rubyonrails.org/mailman/listinfo/rails
> >
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

-- 
John Oxley
Systems Administrator
Yo!Africa
E-Mail:  john at yoafrica.com
Tel:     +263 4 858404
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