[AWDwR] Confused about has_one and has_many

Rails
1

Heya everyone!
I am quite new to Rails and I am reading AWDwR. I am at Task E “Check
Out!”. I understand it quite well, but I have a problem with the last
playground exercise: Add a Table which contains the payment types.
All goes well, but I am not sure whether I should use has_many or
has_one(as in the Playground wiki at
Pragmatic Bookshelf: By Developers, For Developers).

I use the following:

class Order < ActiveRecord::Base
belongs_to :pay_type
…
end

and

class PayType < ActiveRecord::Base
has_many :orders
…
end

Is this right?
Or should I use has_one instead of belongs_to in Order? An order
references to one PayType, Order has one PayType.
I am confused, please help me.

Regards, Thomas

2

I am confused, please help me.
This might be useful to help illustrate things…

http://mboffin.com/stuff/ruby-on-rails-data-relationships.png

3

2007/8/21, Philip H. [email protected]:

This might be useful to help illustrate things…

http://mboffin.com/stuff/ruby-on-rails-data-relationships.png

Ah! Thank you! So just to make it clear: An Order belongs_to a PayType
because the Orders table has an pay_type_id. And PayType has_many
Orders because, many Orders reference to the pay_types table. Right?

4

2007/8/21, Philip H. [email protected]:

This might be useful to help illustrate things…

http://mboffin.com/stuff/ruby-on-rails-data-relationships.png

Ah! Thank you! So just to make it clear: An Order belongs_to a PayType
because the Orders table has an pay_type_id. And PayType has_many
Orders because, many Orders reference to the pay_types table. Right?

Seems right yeah.

5

2007/8/22, Philip H. [email protected]:

Seems right yeah.

Thank you Philip!