Beginner: has_many relationship Active Record Associations

Rails
#1

Hi There,

I got stuck in a Problem with Active Record Associations.

There are some Meals and each meal has many sides.

But it’s only this single direction - so a side don’t need to belong
to the meal. I don’t wanna search: “Give me the meals where side
is …”

I’ll show you the problem with an example:

Meal 1:
Side_8
Side_10
Side_11

Meal 2:
Side_2
Side_8
Side_10

So one Side could be associated with many meals.

But I’m not shure how to create this with active Record.

I thought it should be enough to do this:

class Meal < ActiveRecord::Base
has_many :sides
end

class Side < ActiveRecord::Base
end

But the meal_id is saved at the Side - so a side will only belong to
the last associated Meal - am I right?

Thanks allot for your help
Chris

#2

On 18 Oct 2011 12:56, “Chris” [email protected] wrote:

You want a habtm relationship, or a :through a join model (named like
‘Siding’ to demonstrate its intention to link Side to something).
Consider also that i may order two sides of the same item with one
main…
you need a join table to model that.

#3

On 18 October 2011 13:09, Michael P. [email protected] wrote:

But I’m not shure how to create this with active Record.

You want a habtm relationship, or a :through a join model (named like
‘Siding’ to demonstrate its intention to link Side to something).
Consider also that i may order two sides of the same item with one main…
you need a join table to model that.

Also have a look at the Rails Guide on ActiveRecord Associations.
That may help to clarify things.

Colin