Rails - Dec 2007 - creating intances of a model with two required foreign keys

I asked this the other day but perhaps in too wordy a way.

I have a Student model, a Course_offering model, and a Course_record
model ( a table with columns for grades in midterms, final , lab etc).

The course_record belongs_to both an instance of the Student model and
to an instance of the Course_offering model. I need to create a
collection of course_record instances with the appropriate associations
and I''d like to initialize the name attribute of course_offering to
match the name attribute of the parent Student.

Unfortunately what I have below isn''t working.  I get errors of
"Expected .\app\models\course_record.rb to define Course_record".
@students is an array of student objects and @course_offering is a
particular Course_offering object.


@students.each do |student|
   course_record_foo = Course_record.new( :name => student.name
 :course_offering_id => @course_offering.id,
  :student_id => student.id)
   Course_record.transaction do
      student.course_records << course_record_foo
      @course_offering << course_record_foo
   end
end

I am worried that I might not even be grasping the basic way of creating
an instance of a model requiring "not null" foreign keys ?

Do I need to be manually be setting the foreign keys using create and
stuff like ( :course_offering_id => @coarse_offering.id,  :student_id =>
student.id )? I''m thinking when I associate one it might trigger a save
which would fail because of the other missing foreign key (even in a
transaction).

Is my approach anywhere close to correct and should I be looking for
errors somewhere else perhaps the error is in the database migration
stuff?

Again the error I''m getting is basically: Expected
.\app\models\course_record.rb to define Course_record  (Ive checked and
rechecked for spelling errors of the model etc).
-- 
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On 9 Dec 2007, at 01:02, Tom Norian wrote:
>
> I asked this the other day but perhaps in too wordy a way.
>
> I have a Student model, a Course_offering model, and a Course_record
> model ( a table with columns for grades in midterms, final , lab etc).
>
> The course_record belongs_to both an instance of the Student model and
> to an instance of the Course_offering model. I need to create a
> collection of course_record instances with the appropriate  
> associations
> and I''d like to initialize the name attribute of course_offering
to
> match the name attribute of the parent Student.
>
Just a guess, but the fact that you aren''t using the expected  
convention for class names isn''t going to help (Those should be  
CourseRecord, CourseOffering)
> Unfortunately what I have below isn''t working.  I get errors of
> "Expected .\app\models\course_record.rb to define Course_record".
That usually means that either your naming has confused rails or that  
file contains a syntax error of some sort ( ruby -c checks a file for  
syntax errors)

Fred
> @students is an array of student objects and @course_offering is a
> particular Course_offering object.
>
>
> @students.each do |student|
>   course_record_foo = Course_record.new( :name => student.name
> :course_offering_id => @course_offering.id,
>  :student_id => student.id)
>   Course_record.transaction do
>      student.course_records << course_record_foo
>      @course_offering << course_record_foo
>   end
> end
>
> I am worried that I might not even be grasping the basic way of  
> creating
> an instance of a model requiring "not null" foreign keys ?
>
> Do I need to be manually be setting the foreign keys using create and
> stuff like ( :course_offering_id =>  
> @coarse_offering.id,  :student_id =>
> student.id )? I''m thinking when I associate one it might trigger a
> save
> which would fail because of the other missing foreign key (even in a
> transaction).
>
> Is my approach anywhere close to correct and should I be looking for
> errors somewhere else perhaps the error is in the database migration
> stuff?
>
> Again the error I''m getting is basically: Expected
> .\app\models\course_record.rb to define Course_record  (Ive checked  
> and
> rechecked for spelling errors of the model etc).
> -- 
> Posted via http://www.ruby-forum.com/.
>
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Thank you Fred,  you helped me find a main error I was making.

I was following conventions shown in the AWDwR book where they ran
ruby script/generate model line_item  (pg 132)

Their example shows it in lower case with a spacer.  Is this a bad 
habit?  I seem to recall the script automatically downcasing and spacing 
camel back names anyway.

But what I really missed was that the script/generate model creates a 
class named      LineItem even though the table for migrations is called 
line_items and the model folder would be named line_items.

My examples were course_offering, with a generated class CourseOffering 
NOT what  I was typing: Course_offering.new (there was no such class 
hence the error).

Thanks again for helping out.  Its a funny little quirk to remember 
where the class name is different from the names of the related folders 
and database tables.  It hadn''t been an issue with my single word 
classes.

(btw I went through replaced all the objects in session with object ids 
as you and others warned me about the other day, I welcome any other 
tips about bad habits you see)
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