Rails - Nov 2005 - Comparing field's old value to new value

I want to expire caches if a certain field of an item changes. How can I compare
the item field''s
old value to its new value (in the create, or after_save, etc. method)?

thanks
csn


	
		
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Yahoo! Mail - PC Magazine Editors'' Choice 2005 
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Hi !

There's after_find and after_initialize you can use to copy the
values.  If you have only one or two fields, just override the field's
setter methods:

class X < AR:Base
  def attribute=(new_value)
    old_value ||= read_attribute(:attribute)
    write_attribute(:attribute, new_value)
  end
end

Untested, and I'm not even sure write|read_attribute are the right
method names.  You get the gist, though.

Bye !
François

2005/11/27, CSN <cool_screen_name90001@yahoo.com>:
> I want to expire caches if a certain field of an item changes. How can I
compare the item field's
> old value to its new value (in the create, or after_save, etc. method)?
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