From: ara.t.howard@...
Date: 2007-02-15T11:46:28+09:00
Subject: Re: Creating a second instance of a singleton class?

On Thu, 15 Feb 2007, Steve Midgley wrote:

> I love this group b/c there are so many clever people here. Ara - you're 
> definitely getting me close.
>
> I'll open the bag a little at the expense of brevity so you can see what I'm 
> trying to accomplish. I'm using Rails v1.2.2, and in particular ActiveRecord 
> 1.15.2.
>
> In the course of a data operation, I have a series of active record 
> instances:
>
> instance1ofclass1, instance2ofclass1, instance1ofclass2, instance2ofclass2, 
> etc..]
>
> For any given activerecord class for the above list (let's use an example 
> table called "property") there is an identical table (less the primary key) 
> called "property_versions"
>
> I would like to be able to create a new instance of the activerecord model 
> but using a new table name - changing the table_name is handled as a class 
> method "set_table_name(new_name)"
>
> So I could say:
>
> #==> assumes we have a "property" instance available..
> orig_table = Property.table_name
> class Property
>  set_table_name 'property_versions'
> end
>
> prop_versions = Property.new(property.attributes)
>
> class Property
>  set_table_name orig_table
> end

you lost me.  why wouldn't you just do

   property_versions_class = Class.new(Property){ set_table_name 'property_versions' }

   prop_versions = property_versions_class.new(property.attributes)

??

and that's assuming it had to be dynamic.  for that matter why not

   ./script/generate model PropertyVersion

and

   prop_versions = PropertyVersion.new(property.attributes)

??


-a
-- 
we can deny everything, except that we have the possibility of being better.
simply reflect on that.
- the dalai lama