I have three classes defined like this:
class Campaign < ActiveRecord::Base
has_many :urls, :foreign_key => 'campaignid' has_many :stats, :through => :urls
set_table_name 'campaign' set_primary_key 'campaignid' end
class Url < ActiveRecord::Base belongs_to :campaign, :foreign_key => 'campaignid' has_many :stats, :foreign_key => 'urlid'
set_table_name 'url' set_primary_key 'urlid' end
class Stat < ActiveRecord::Base belongs_to :url, :foreign_key => 'urlid'
set_primary_key 'statsid' end
When I drop into the console and try this:
c = Campaign.find(:first) c.stats
I get this:
ActiveRecord::StatementInvalid: Mysql::Error: #42S22Unknown column 'url.statsid' in 'on clause': SELECT `stats`.* FROM `stats` INNER JOIN url ON stats.urlid = url.statsid WHERE ((`url`.campaignid = 1)) from /Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/connection_adapters/abstract_adapter.rb:147:in `log'
It looks like the inner join is being improperly constructed. It should say
INNER JOIN ON stats.urlid = url.urlid
Or, to put it more generically:
INNER JOING ON <association_table>.<intermediate_table_fk> = <intermediate_table>.<intermediate_table_pk>
But it is currently doing:
INNER JOING ON <association_table>.<intermediate_table_fk> = <intermediate_table>.<associate_table_pk>
I think this boils down to activerecord-2.1.0/lib/active_record/associations/has_many_through_association.rb:150-155
I think this would be easy to miss since :through associations aren't entirely common and renaming your primary key is also not common so any table's primary key is getting used. I'm going to do a workaround that doesn't use the :through association for now.