Object attributes through habtm


#1

Hi all,

I have some “strange” behavior going on in one of my Rails apps.
I have two models: CustomerCategory and PaymentType. Both have a HABTM
relationship.

If I want to know the attributes of a PaymentType, I do
PaymentType.find(1).attributes. This nicely returns a hash with all the
attribute names and values (let’s say {“name” => “mastercard”}).

The strange thing that happens however is that when I get the payment
type through a customer category, suddenly payment_type_id is added as
an attribute to the payment type object. So
CustomerCategory.find(1).payment_types[0].attributes returns
{“payment_type_id” => “1”, “name” => “mastercard”}.

Is this a Rails feature or a bug?

Regards,

Wouter


#2

On May 14, 2:57 pm, Wouter de Bie removed_email_address@domain.invalid
wrote:

The strange thing that happens however is that when I get the payment
type through a customer category, suddenly payment_type_id is added as
an attribute to the payment type object. So
CustomerCategory.find(1).payment_types[0].attributes returns
{“payment_type_id” => “1”, “name” => “mastercard”}.

Is this a Rails feature or a bug?

It’s a semi deprecated feature: getting attributes from the join table
automatically. The trend has since been to make that join table a
model in its own right.

Fred


#3

Frederick C. wrote:

It’s a semi deprecated feature: getting attributes from the join table
automatically. The trend has since been to make that join table a
model in its own right.

Fred

I know that I can use a has_many :through, but sometimes habtm is better
in my application, since it doesn’t clutter my project so much with
models I don’t use, except for the relationship. For relations that
require more functionality, I use has_many :through.