# SQL/Model for Customers Who Bought This Item Also Bought **URL:** \ **Category:** Rails\ **Created:** [November 10, 2007, 9:39pm UTC](https://www.ruby-forum.com/t/sql-model-for-customers-who-bought-this-item-also-bought/119815 "2007-11-10T21:39:45Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![thabenksta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/97f17d/32.png) [@thabenksta](https://www.ruby-forum.com/u/thabenksta)\ **Post date:** [November 10, 2007, 9:39pm UTC](https://www.ruby-forum.com/t/sql-model-for-customers-who-bought-this-item-also-bought/119815/1 "2007-11-10T21:39:45Z")
Hello. We have a decent size Rails application that has worked great for us using ActiveRecord with minimal custom SQL here and there. However, now we need to develop a feature very similar to Amazon’s “Customers Who Bought This Item Also Bought” feature. I’m looking for suggestions on best ways to handle this, via real-time using the actual table or a periodic process that updates a different table (e.g. nightly). Any suggestions on how to design one or more tables would be greatly appreciated! Thanks in advance. ---
**Author:** ![thabenksta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/97f17d/32.png) [@thabenksta](https://www.ruby-forum.com/u/thabenksta)\ **Post date:** [November 11, 2007, 6:01am UTC](https://www.ruby-forum.com/t/sql-model-for-customers-who-bought-this-item-also-bought/119815/2 "2007-11-11T06:01:17Z")
On Nov 10, 12:39 pm, Ben K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Any suggestions on how to design one or more tables would be greatly > appreciated! > > ## Thanks in advance. > > Posted viahttp://www.ruby-forum.com/. i searched on “rails +collaborative +filtering” and didn’t find much, but there are lots of papers on methodology.