Rails 1.2.2 HABTM error?

rubyonrails-talk
1

Hi. I have the following models:

class User < ActiveRecord::Base   has_and_belongs_to_many :rooms end

class Room < ActiveRecord::Base   has_and_belongs_to_many :users end

And the test:

require File.dirname(__FILE__) + '/../test_helper'

class RoomTest < Test::Unit::TestCase

  def test_habtm     u1 = User.create     u2 = User.create

    r1 = Room.create     r2 = Room.create

    r1.users << u1     r1.users << u2     r2.users << u2   end end

Running "rake test" results in the failure:

  1) Error: test_habtm(RoomTest): ActiveRecord::StatementInvalid: Mysql::Error: Duplicate entry '2' for key 1: INSERT INTO rooms_users (`id`, `user_id`, `room_id`) VALUES (2, 2, 2)

The problem is, that Rails for some reason sets the "id" of the rooms_users record to 2, rather than letting MySQL autoincrement handle it.

Is this an error or am I missing something? Thanks.

Morten

2

Remove the id column from your join table and all will be well. Rails doesn't like surrogate keys on join tables, unless you model the join.

Ciao, Sheldon.