Mapping active record objects to virtual attributes

I’ve got a phone number field defined in a model as a single String.
However, the form used to input the phone number exposes the number as
three distinct fields to help the user enter the number in the correct
format. I’m mapping the three input parameters to the single string
in a before_validation method which seems to work fine, but I want to
be able to map the single string to the three distinct fields when the
record is loaded from the database. What’s the correct hook to do
that? I tried to provide a phone_number= method that used
self[:phone_number]=… to assign the attribute and then split the
phone number up into the three fields to be returned by accessors, but
AR doesn’t seem to call this method when the record is loaded from the
database. What’s the best way to accomplish this?

On Jan 31, 2008 3:10 PM, bigbanger [email protected] wrote:

phone number up into the three fields to be returned by accessors, but
AR doesn’t seem to call this method when the record is loaded from the
database. What’s the best way to accomplish this?

class MyModel < ActiveRecord::Base

def after_find
# call your method to split the phone number here
end

Another way to do this is with a virtual accessors

def area_code
phone_number[0…2]
end

def area_code=(area_code)
raise ArgumentError.new(‘invalid area code’) unless
area_code.length == 3
phone_number[0…2] = area_code
end

of course this will differ depending just how you represent the numbers.


Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

Rick Denatale wrote:

On Jan 31, 2008 3:10 PM, bigbanger [email protected] wrote:

phone number up into the three fields to be returned by accessors, but
AR doesn’t seem to call this method when the record is loaded from the
database. What’s the best way to accomplish this?

I figured out how to use Aggregations to provide the necessary piecing
and reassembly of phone number
http://blogs.entertonement.com/nerdery/2008/07/rails-multipara.html

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs