Rails - Aug 2007 - How would I find all "Exams" that belong to a "Student"?

I know this is wrong:

@exams = Exam.find(:all, :conditions => ["class.student_id = ?",
current_user.id])

How would I correct the above to make it work?

I know I can''t have class.student_id, since that''s not a
column name in
the database table.

Beyond that, I have no idea how to find all exams that belongs to a
student.

Any input?
-- 
Posted via http://www.ruby-forum.com/.

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Hi, if you have the following models
class Student < ActiveRecordBase
   has_and belongs_to_many :exams
end

class Exam < ActiveRecordBase
   has_and_belongs_to_many :students
end

# What exams did a student take
student = Student.find( student_id )
exams_taken = student.exams

For a better explaination of Rails relationships, I would highly recommend
reading AWDwRv2 chapter 18.

Good luck,

-Conrad


On 8/5/07, Bob Sanders
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
>
>
> I know this is wrong:
>
> @exams = Exam.find(:all, :conditions => ["class.student_id =
?",
> current_user.id])
>
> How would I correct the above to make it work?
>
> I know I can''t have class.student_id, since that''s not a
column name in
> the database table.
>
> Beyond that, I have no idea how to find all exams that belongs to a
> student.
>
> Any input?
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
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Leave class out of it, as the id is not relative to the class.

So:

user.rb model:
has_many :exams
belongs_to :class

exam.rb model:
belongs_to :user

controller:
user = User.find(current_user.id)
user.exams #=> [1,Math], [2,English], etc.


Cheers,
Zach Inglis
→ Blog -- http://www.zachinglis.com
→ Company -- http://www.lt3media.com
→ Portfolio -- http://portfolio.zachinglis.com


On Aug 5, 2007, at 7:13 PM, Bob Sanders wrote:
>
> I know this is wrong:
>
> @exams = Exam.find(:all, :conditions => ["class.student_id =
?",
> current_user.id])
>
> How would I correct the above to make it work?
>
> I know I can''t have class.student_id, since that''s not a
column
> name in
> the database table.
>
> Beyond that, I have no idea how to find all exams that belongs to a
> student.
>
> Any input?
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

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U can do: student.exams assuming u have student has-many exams  
declaration in ur student model

Sent from my iPhone

On Aug 5, 2007, at 4:13 AM, Bob Sanders
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org
 > wrote:
>
> I know this is wrong:
>
> @exams = Exam.find(:all, :conditions => ["class.student_id =
?",
> current_user.id])
>
> How would I correct the above to make it work?
>
> I know I can''t have class.student_id, since that''s not a
column name
> in
> the database table.
>
> Beyond that, I have no idea how to find all exams that belongs to a
> student.
>
> Any input?
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >
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