Rails - Mar 2006 - polymorphism + inheritance

Hi,

currently I do some work with polymorphic associations in egde rails

class Order < ActiveRecord::Base
  belongs_to :payment, :polymorphic => true
end

class CreditCardPayment < Payment
end

class PayPalPayment < Payment
end

class Payment < ActiveRecord::Base
  has_one :order, :as => :payment
  # common stuff in here
end

I want to use [Payment] for common functionality typical to payments.

However, this will throw an error:
>> CreditCardPayment.create(...)
ActiveRecord::StatementInvalid: Mysql::Error: #42S02Table
''demo.payments''
doesn''t exist: SHOW FIELDS  FROM payments

Is there a way to convince ActiveRecord that [Payment] is an abstract base
class that does not need to exist (and take the name of the concrete class
for determining the table name) ?

Thanks in advance!!

Best regards
Peter

Looks like you''re trying to use single table inheritance here.

http://wiki.rubyonrails.com/rails/pages/SingleTableInheritance

This requires a "payments" table with a "type" column for
storing the actual
class of the row ("CreditCardPayemnt" or "PayPalPayement" or
...)

On 3/27/06, Peter Ertl <pertl@gmx.org> wrote:
>
> Hi,
>
> currently I do some work with polymorphic associations in egde rails
>
> class Order < ActiveRecord::Base
>   belongs_to :payment, :polymorphic => true
> end
>
> class CreditCardPayment < Payment
> end
>
> class PayPalPayment < Payment
> end
>
> class Payment < ActiveRecord::Base
>   has_one :order, :as => :payment
>   # common stuff in here
> end
>
> I want to use [Payment] for common functionality typical to payments.
>
> However, this will throw an error:
> >> CreditCardPayment.create(...)
> ActiveRecord::StatementInvalid: Mysql::Error: #42S02Table
''demo.payments''
> doesn''t exist: SHOW FIELDS  FROM payments
>
> Is there a way to convince ActiveRecord that [Payment] is an abstract base
> class that does not need to exist (and take the name of the concrete class
> for determining the table name) ?
>
> Thanks in advance!!
>
> Best regards
> Peter
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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