Maintaining order when I call Video.find("3", "1", "2")

rubyonrails-talk
1

If I call Video.find("3", "1", "2"), it'll give me all the videos but the orders will be with ids 1, 2, and 3. I want to maintain the order that I pass it in. Is there a quick easy way to do that? Either sorting in the db or with Ruby.

Pat

2

I think your best bet is to separate them out into separate SQL statements. The connection adapter is translating that into something like:

SELECT ... FROM videos WHERE id IN (3,1,2);

The result set from the database will most likely come out in DB-natural order, which probably works out to PK order. In any case, it is database dependent and I can't think of an easy way to get the result set in a particular order. You can always do

ids.map {|id| Video.find(id)}

but of course it multiplies the number of queries by n.

Brad

3

For a quick stab

video_ids = [3,1,2] videos_temp = Video.find( *video_ids ) videos = video_ids.map{ |vid| videos_temp.detect{ |video| video.id == vid } }

Whoa that’s ugly.

4

If I call Video.find(“3”, “1”, “2”), it’ll give me all the videos but the orders will be with ids 1, 2, and 3. I want to maintain the order that I pass it in. Is there a quick easy way to do that? Either sorting in the db or with Ruby.

Pat

For a quick stab

video_ids = [3,1,2] videos_temp = Video.find( *video_ids ) videos = video_ids.map{ |vid| videos_temp.detect{ |video| video.id == vid } }

Whoa that’s ugly.

Hopefully this isn’t:

ids = [36, 27, 35]

=> [36, 27, 35]

products = Product.find ids

=> […stuff…]

products.size

=> 3

products.map(&:id)

=> [27, 35, 36]

products**.sort_by {|p| ids.index(p.id)}**.map(&:id)

=> [36, 27, 35]

ids

=> [36, 27, 35]

-Rob

Rob Biedenharn http://agileconsultingllc.com

Rob@AgileConsultingLLC.com