On Wednesday, May 25, 2011 9:06:49 AM UTC-6, Mlle wrote:
>
> If I wanted to write my own db trigger using a 'before_save" callback,
> how would I get the before save and after save values?
>
> Thanks!
By "before save and after save values" do you mean the original, unchanged
value(s) of the propert(y|ies) and the new, changed value(s)?
If so, you might be interested in #changed_attributes. If you call this on a
model instance, it returns a hash where the keys are the names of the model
attributes that have changed and the associated values are original values.
For example:
> x = User.find(1)
=> #<User id: 1, name: "Bill", ...>
> x.changed?
=> false
> x.name
=> "Bill"
> x.name = "Fred"
=> "Fred"
> x.changed?
=> true
> x.changed_attributes
=> { "name" => "Bill" }
> x.save
=> true
> x.changed?
=> false
> x.changed_attributes
=> {}
For more information:
http://api.rubyonrails.org/classes/ActiveModel/Dirty.html
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