Strange bug in has_and_belongs_to_many

Hello everyone.

I have two Classes, linked by a HABTM relationship.

class Building < ActiveRecord::Base
set_table_name ‘gc_edifici_attivita’
has_and_belongs_to_many :jobs, :join_table =>
‘gc_edificio_avvio_commessa’, :foreign_key =>
‘edificio_attivita_gc_id’, :class_name => ‘Job’


class Job < ActiveRecord::Base
set_table_name ‘gc_avvio_commessa’

has_and_belongs_to_many :buildings, :join_table
=>‘gc_edificio_avvio_commessa’, :foreign_key =>
‘commessa_id’, :class_name => ‘Building’, :association_foreign_key =>

Ok, table names are in Italian… that’s because I had to use a legacy
database and could not change the tables’ names.

Now, for each Job, I have to list all the Buildings related to it. So
it goes like this:

@jobs = Job.all

@jobs.each do |job|
job.buildings [… do something with the buildings…]

Everything goes well so far. But sometimes, I have to list only the
Jobs happening on a given Building, yielding:

@jobs = Building.find(params[:building]).jobs
@jobs.each do |job|
job.buildings [… do something with the buildings…]

This won’t work anymore; Rails keeps telling me there’s no such method
as ‘buildings’ for class ‘Job’. it’s almost as if collecting the Jobs
from a Building through HABTM, Rails cannot ‘see’ what methods are in
class Job.

Any ideas about this? Is there a bug in Rails, or is this supposed to
Thanks in advance to anyone who might help me.


Under your Job class you have an association_foreign_key, do you need a
comparable line under your building class as well? This will depend on
what your join table looks like.

Otherwise, I don’t see any problems.