STI and has_many :through not playing nicely

Rails
1

Hi all,

I’m trying to use STI (single table inheritance) with
has_many :through, and I’m getting a NameError: uninitialized
constant. Details below. Presumably I’ve set up the relationship
incorrectly? Any help would be greatly appreciated!

I have the following models:

class Activity < ActiveRecord::Base

has_many :memberships
has_many :members, :through => :memberships

class Branch < Activity

class Member < ActiveRecord::Base

has_many :memberships
has_many :activities, :through => :memberships

class Memberships < ActiveRecord::Base

belongs_to :members
belongs_to :activities

I’m trying to run the following test (the activity fixture I’m testing
is a branch):

class ActivityTest < Test::Unit::TestCase
fixtures :activities, :members, :memberships

Replace this with your real tests.

def test_has_member
assert_equal activities(:bristol).members.empty?, false
end
end

and it’s failing with:

NameError: uninitialized constant Activity::Membership

2

On 7 Apr, 01:45, Mark Reginald J. [email protected] wrote:

You want

 belongs_to :member
 belongs_to :activity

Thanks Mark, but I still get the same error. Any more suggestions?

Cheers,

Tom

3

Tom T. wrote:

class Memberships < ActiveRecord::Base

belongs_to :members
belongs_to :activities

You want

 belongs_to :member
 belongs_to :activity

–
We develop, watch us RoR, in numbers too big to ignore.

4

On 7 Apr, 10:24, Mark Reginald J. [email protected] wrote:

Yes, it should also be “class Membership” rather than “class Memberships”.

Thanks, but alas, the same result…

Cheers,

Tom

5

Tom T. wrote:

On 7 Apr, 01:45, Mark Reginald J. [email protected] wrote:

You want

 belongs_to :member
 belongs_to :activity

Thanks Mark, but I still get the same error. Any more suggestions?

Yes, it should also be “class Membership” rather than “class
Memberships”.

–
We develop, watch us RoR, in numbers too big to ignore.

6

On 7 Apr, 10:39, “Tom T.” [email protected] wrote:

The full stack trace is:

Doh! I hadn’t renamed memberships.rb to membership.rb. All fixed,
thanks Mark!

7

On 7 Apr, 10:35, “Tom T.” [email protected] wrote:

Thanks, but alas, the same result…

The full stack trace is:

  1. Error:
    test_has_member(ActivityTest):
    NameError: uninitialized constant Activity::Membership
    /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/
    dependencies.rb:477:in const_missing' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/ base.rb:1360:in compute_type’
    /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/
    reflection.rb:125:in klass' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/ reflection.rb:177:in source_reflection’
    /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/
    reflection.rb:177:in source_reflection' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/ reflection.rb:186:in check_validity!’
    /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/
    associations/has_many_through_association.rb:6:in initialize' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/ associations.rb:934:in members’
    ./test/unit/activity_test.rb:7:in `test_has_member’