Rails - May 2006 - Queries with has_and_belongs_to_many relationship

I was able to create a has_and_belongs_to_many relationship for my app, 
but now I''m not too sure how to write queries for it.

Basically, I have a table ''courses'' that
has_and_belongs_to_many
''categories'' and vice versa

So I''m trying to figure out how I would find only the courses that 
belong to a category that I specify.

Let''s say the category is ''math'' and the categories
are in a column
named ''name''

Any help would be great.

-- 
Posted via http://www.ruby-forum.com/.

Category.find(:first, :condition => "name = math").courses

Or something to that effect should do the trick.

On 5/7/06, Ben <whywontitletme@yahoo.com> wrote:
> I was able to create a has_and_belongs_to_many relationship for my app,
> but now I''m not too sure how to write queries for it.
>
> Basically, I have a table ''courses'' that
has_and_belongs_to_many
> ''categories'' and vice versa
>
> So I''m trying to figure out how I would find only the courses that
> belong to a category that I specify.
>
> Let''s say the category is ''math'' and the
categories are in a column
> named ''name''
>
> Any help would be great.
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

--
Ben Reubenstein
303-947-0446
http://www.benr75.com

@courses_in_cat = Category.find_by_name(''math'',
:first).courses

This should give you back an array for all the courses in the math category.

The opposite is also true.

@categories_for_course = Course.find_by_name(''some course'',
:first).categories

To add Courses to a Category
@some_category << @an_array_of_courses
and vise versa
@some_course << @an_array_of_categories


On 5/8/06, Ben <whywontitletme@yahoo.com> wrote:
> I was able to create a has_and_belongs_to_many relationship for my app,
> but now I''m not too sure how to write queries for it.
>
> Basically, I have a table ''courses'' that
has_and_belongs_to_many
> ''categories'' and vice versa
>
> So I''m trying to figure out how I would find only the courses that
> belong to a category that I specify.
>
> Let''s say the category is ''math'' and the
categories are in a column
> named ''name''
>
> Any help would be great.
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>