On Sun, Jun 15, 2014 at 1:29 AM, Ronald Fischer <[email protected]> wrote:
> Card.where(box_id: params[:box_id]).map {|c| c.id }.each do |cid|
> # .... Do something with cid
> end
> This is compact, but I don't like the fact that first, all data from the
> retrieved Card objects needs to be stored in memory at least temporarily
> (there is even a 'text' field in Card!), but only the id is needed.
> I wonder whether there is a simpler solution, using just
> ActiveRecord functions.
As Colin pointed out,
(assume that ) box = Box.find(box_id)
box.cards # has the cards you want *if* you need all the attributes
box.cards.pluck(:id) # builds a query to fetch *only* the card ids
HTH,
--
Hassan Schroeder ------------------------ [email protected]
http://about.me/hassanschroeder
twitter: @hassan
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