Rails - Jan 2006 - create and update with has_many :through

I''m using Edge Rails and the new has_many :through in my code. What  
I''m trying to do is modify my create and update code to use the new  
relationships. I''m using a table called course_teachers for the joins.

Here is what I have so far:

	def create
	  @course = Course.new(params[:course])
		@teacher = Teacher.find(params[:primary_teacher])

		@course.teachers = @teacher
		
	  if @course.save
	    flash[:notice] = ''Course was successfully created.''
	    redirect_to :action => ''show'', :id => @course
	  else
	    render :action => ''new''
	  end
	end



	def update
	  @course = Course.find(params[:id])
		# New primary teacher
		@teacher = Teacher.find(params[:primary_teacher])
		
		# Clear primary teacher for course.
		@course.course_teachers.update_all("is_primary = 0")
		
		# Need this to add the teacher to the course_teachers join table or  
update the teacher
		# as primary if they are already associated with this course.
		@course.teachers = @teacher
		
	
	  if @course.update_attributes(params[:course])
	    flash[:notice] = ''Course was successfully updated.''
	    redirect_to :action => ''show'', :id => @course
	  else
	    render :action => ''edit''
	  end
	end


Thanks,
Kyle

How have you defined your models, and what is the problem you are
having?

-Jonny.

Kyle Mathews wrote:
> I''m using Edge Rails and the new has_many :through in my code.
What
> I''m trying to do is modify my create and update code to use the
new
> relationships. I''m using a table called course_teachers for the
joins.
> 
>
-- 
Posted via http://www.ruby-forum.com/.

My models are the following:

class Course < ActiveRecord::Base
	has_many :course_teachers
	has_many :teachers, :through => :course_teachers
end

class CourseTeacher < ActiveRecord::Base
	belongs_to :course
	belongs_to :teacher
end

class Teacher < ActiveRecord::Base
	has_many :course_teachers
	has_many :courses, :through => :course_teachers
end


I get the following error if I try to create a new course and add the  
primary teacher.

undefined method `teachers='' for #<Course:0x243ff00>

Thanks,
Kyle


On Jan 23, 2006, at 3:38 PM, Jonathan Viney wrote:
> How have you defined your models, and what is the problem you are
> having?
>
> -Jonny.
>
> Kyle Mathews wrote:
>> I''m using Edge Rails and the new has_many :through in my code.
What
>> I''m trying to do is modify my create and update code to use
the new
>> relationships. I''m using a table called course_teachers for
the
>> joins.
>>
>>
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Kyle,

You need to use the join model class when creating your associations. 
You were trying to set the association''s accessor method to a single
course object.

Try something like this:

course = Course.create(:name => ''English 101'')
teacher = Teacher.create(:name => ''Mr. Smith'')

course.course_teachers.create(:teacher => teacher) # Creates and saves
a new CourseTeacher object.

You could also explicitly create the join model object:
course_teacher = CourseTeacher.new(:course => course, :teacher => teacher)
course_teacher.save

# Get the associated objects
course.reload # Don''t forget to reload if you didn''t add the
object
through the collection
course.course_teachers
course.teachers


Cody


On 1/23/06, Kyle Mathews <kyle@titaniumdev.com>
wrote:
> My models are the following:
>
> class Course < ActiveRecord::Base
>         has_many :course_teachers
>         has_many :teachers, :through => :course_teachers
> end
>
> class CourseTeacher < ActiveRecord::Base
>         belongs_to :course
>         belongs_to :teacher
> end
>
> class Teacher < ActiveRecord::Base
>         has_many :course_teachers
>         has_many :courses, :through => :course_teachers
> end
>
>
> I get the following error if I try to create a new course and add the
> primary teacher.
>
> undefined method `teachers='' for #<Course:0x243ff00>
>
> Thanks,
> Kyle
>
>
> On Jan 23, 2006, at 3:38 PM, Jonathan Viney wrote:
>
> > How have you defined your models, and what is the problem you are
> > having?
> >
> > -Jonny.
> >
> > Kyle Mathews wrote:
> >> I''m using Edge Rails and the new has_many :through in my
code. What
> >> I''m trying to do is modify my create and update code to
use the new
> >> relationships. I''m using a table called course_teachers
for the
> >> joins.
> >>
> >>
> >
> > --
> > Posted via http://www.ruby-forum.com/.
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

--
http://www.codyfauser.com