2 files changed, 17 insertions, 8 deletions
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 26987dde97..e12f6be35d 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -302,6 +302,15 @@ module ActiveRecord
         end
       end
 
+      # Returns true if the collection has more than 1 record. Equivalent to collection.size > 1.
+      def many?
+        if block_given?
+          method_missing(:many?) { |*block_args| yield(*block_args) }
+        else
+          size > 1
+        end
+      end
+
       def uniq(collection = self)
         seen = Set.new
         collection.inject([]) do |kept, record|
diff --git a/activerecord/lib/active_record/associations/has_one_through_association.rb b/activerecord/lib/active_record/associations/has_one_through_association.rb
index 8073ebaf9f..d93c8e7852 100644
--- a/activerecord/lib/active_record/associations/has_one_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_through_association.rb
@@ -1,31 +1,31 @@
 module ActiveRecord
   module Associations
     class HasOneThroughAssociation < HasManyThroughAssociation
-      
+
       def create_through_record(new_value) #nodoc:
         klass = @reflection.through_reflection.klass
 
         current_object = @owner.send(@reflection.through_reflection.name)
-        
+
         if current_object
-          current_object.update_attributes(construct_join_attributes(new_value))
+          new_value ? current_object.update_attributes(construct_join_attributes(new_value)) : current_object.destroy
         else
-          @owner.send(@reflection.through_reflection.name,  klass.send(:create, construct_join_attributes(new_value)))
+          @owner.send(@reflection.through_reflection.name,  klass.send(:create, construct_join_attributes(new_value))) if new_value
         end
       end
-      
+
     private
       def find(*args)
         super(args.merge(:limit => 1))
       end
-    
+
       def find_target
         super.first
       end
 
       def reset_target!
         @target = nil
-      end        
-    end        
+      end
+    end
   end
 end