So in Chris' approach, I could do:
[code]
@product=products[0].clone
@product.id=products[0].id
@product.save!
[/code]
And this would work except that I have 'before_create' filters on
Product, and for some reason clone() loses all of the methods that
should be there. For example, self.kind='something' doesn't work in a
filter for @product as generated above. I can't rewrite all of the
before filters to muck around in the @attributes variable, because there
are just too many models to rewrite for this exception.
So, I'm settling for Evan's approach, using the "write_attribute"
function (which I see is also mentioned in the comments of
"active_record/base.rb") and removing the default value in the table
definition. It's not what I would like to do, but it is a step forward.
Thanks for your help; I hope this helps others on the list as well. If
anyone knows of a cleaner approach . . .
Thanks!
-Cassius
Evan wrote:
> You can force a specific primary key by adding an id writer method to
> your model:
>
> def id= n; write_attribute :id, n; end
>
> Then after instantiating the object with .new(hash), you can assign
> .id= the new id. Then you can save the record and it will go in with
> the id you want. (At least, that's how I worked around the problem in
> my own code).
>
> I don't know why your "kind" attribute isn't getting saved properly,
> though.
>
> Evan
>
>
> On 10/18/06, Cassius Rosenthal <cassius@xmodulation.com> wrote:
>> Interesting approach. This breaks filters because the YAML object uses
>> strings instead of symbols to hash the attributes. Substituting strings
>> into filter functions [is ugly but] does solve the problem of :kind in
>> the example below overriding the table default; however, the id for the
>> object still is not preserved. In this case, it defaults to the
>> postgres sequence. So this approach still doesn't work.
>>
>> This may be obvious, but building on my example below, the sql:
>> "INSERT INTO products VALUES (42,'apple','fruit');"
>> works perfectly, and is the sql that I expect/wish to be generated by
>> Rails.
>>
>> Any other ideas?
>>
>> Thanks!
>> -Cassius
>>
>>
>> Chris wrote:
>> > Try products[0].clone rather than creating a new object.
>> >
>> > Cassius Rosenthal wrote:
>> >> This is one of those questions where I knew how to do what I want to,
>> >> but I can't for the life of me remember how to do it. I should know
>> >> this, but I just can't seem to find the answer from The Brain (ie.,
>> >> googling didn't help).
>> >> Say I have a model Product. I create the table as follows:
>> >> [code]
>> >> create_table :products, :force => true do |t|
>> >> t.column :name, :string
>> >> t.column :kind, :string, :default=>"pizza"
>> >> end
>> >> [/code]
>> >>
>> >> I then load a product from a fixture:
>> >> [code]
>> >> products=YAML::load(foo.yml)
>> >> [/code]
>> >> #products[0].attributes=>
>> >> {:id=>"42", :name=>"apple", :kind=>"fruit"}
>> >> So far, so good. Note the id of 42, which is important because this
>> >> object relates to another model, and I want to preserve the primary
>> >> keys.
>> >>
>> >> Then I instantiate a new ActiveRecord from this data:
>> >> [code]
>> >> @product=Product.new(products[0].attributes)
>> >> [code]
>> >> #@products=>
>> >> {:id=>"1", :name=>"apple", :kind=>"pizza"}
>> >> Ack! ActiveRecord used the table defaults instead of the attributes
>> >> that I sent to the object. How do I override this behavior?
>> >>
>> >> Thanks!
>> >> -Cassius
>> >> _______________________________________________
>> >> talk mailing list
>> >> talk@phillyonrails.org
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>> >>
>> >
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>> >
>>
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>
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