I have two classes with a one-to-many relationship, and want to find all A records that don't have any B records. I can't seem to make a B.find(:all, :conditions => "blah") work because the foreign key is in A. Any help would be appreciated...
This is essentially what I have:
class A < ActiveRecord::Base has_many :B end
class B < ActiveRecord::Base belongs_to :A end
Am I going to have to do a :join to make this work with one sql statement? (Just to move on I wrote the following, but I know it is the wrong way to do it, just including so you can see the result I want to achieve.. )
def self.no_B ret = Array.new
self.find(:all, :include => :B ).each do |a| ret << a if a.B.empty? end ret end