The thing I probably enjoy most about working with Rails is that it makes it easier to put logic in the right place than not to. To get back in the swing of blogging after a light couple of weeks, I thought it might be useful to run through an example of how that’s worked out for me recently. From time to time I’ve been working on an application that will contain a database of musicians. To be able to add new musicians quickly I’ve been using: ...
Along with Bill Eisenhauer, I’ve been digging into what it would take to fix the problem I found with GeoKit, that it wouldn’t support :include queries properly. The explanation has seen us going deep into the internals of ActiveRecord to discover, as others have before, that the :select parameter (which GeoKit uses to build its distance column in the query) and the :include parameter don’t play nicely together. The reason for that is that Rails employs special methods to build the select parameters when there’s a :include in the query (ie. when you’re joining with other tables and eager-loading them) and currently ignores :select along the way. GeoKit would ordinarily produce SQL along the lines of: ...
UPDATE (10/2008): This plugin is no longer maintained. I’d recommend looking at one of the newer alternatives such as acts_as_amazon_product if you need this functionality. I’ve been procrastinating on getting my first Ruby on Rails plugin (first anyone else might be interested in, at least) out the door, mainly due to some configuration problems with Subversion, but finally I have that all sorted out and the plugin ready to go. loads_from_amazon is an ActiveRecord Mixin that works with the Ruby/Amazon library to let you populate an ActiveRecord object with the details of a product listed on amazon. In the README I use the following example: ...