Help with habtm

[Gm]

Hi,

I'm using habtm to create a relationship between two models:

class Question < ActiveRecord::Base

  has_and_belongs_to_many :exams

end

class Exam < ActiveRecord::Base

  has_and_belongs_to_many :questions

end

At some point I'm doing this:

class Exam < ActiveRecord::Base

   has_and_belongs_to_many :questions

   def generate

      (1..5).each do

         questions.create(Question::SKELETON)

      end

   end

end

When I do that, a sql inserts a record inside questions_exams table.

But this table has another column called: 'order' where I need to put some data inside

How can I populate the 'order' column inside join table ?

questions_exams

   - question_id

   - exam_id

   - order

Thanks.

[Colin Law]

Don't use habtm, use has many through
Exam has_many questions_exams
has_many questions through questions_exams

But probably don't call it questions_exams, think of a better name

In fact even when I could use habtm I usually use has many through, I
find it easier to understand. Also it is surprising how often the
requirement for a little something extra in the join table pops up out
of the requirements when least expected.

Colin

[Gm]

Hi Colin,

Thanks for the reply.

Even if I use has many through, how can I populate the order field dinamically ?

When I do this:

   def generate

      (1..5).each do

         questions.create(Question::SKELETON)

      end

   end

Thank you.

[Colin Law]

On 26 March 2015 at 20:38, Gm <javap...@gmail.com> wrote:
> Hi Colin,
>
> Thanks for the reply.
>
> Even if I use has many through, how can I populate the order field
> dinamically ?
> When I do this:
>
> def generate
> (1..5).each do
> questions.create(Question::SKELETON)
> end
> end

Possibly something like
exam.questions_exams.create(order: something).create_question(...)

You can find detailed definitions of the methods that the associations
provide in section 4 of
http://guides.rubyonrails.org/association_basics.html

Colin

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