On Jan 12, 2010, at 9:46 AM, Steve Castaneda wrote:
Owners has_one :widget and Widgets belongs_to :owner. When creating a
new widget, I'm giving the option for the user to specify the owner by
using a drop down select. The select is populated by pulling a list
of
owners.
What would be the best way to populate the select with owners who do
not
have a widget?
I'm assuming my controller would look something like this for Widgets:
--
def new
@widget = Widget.new
@widgets = Widget.find(:all)
@owners = Owners.find(:all, :conditions => '...this is where I go
blank...')
end
--
I'm assuming that it has to go in some kind of condition. Am I
supposed
to run the owners find through some sort of block to validate for each
widget I've found in @widgets?
@owners = Owner.all(:conditions => 'widget_id IS NULL')
Would do it. Assuming that it's correct to say that if widget_id is
null they have no widget -- this wouldn't catch instances where say an
owner *had* widget, the widget was removed and the owners widget_id
wasn't set back to null.
@owners = Owner.all.reject{|o| o.widget.nil? }
Would also do it. This has the drawback that the DB is going to
return *all* the owners and then filter them in ruby. Won't be as
speedy as the first option.
You probably want to add an :order option to whichever one you use to
get a consistent output.
-philip
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