This post originated from an RSS feed registered with Ruby Buzz by Obie Fernandez. Original Post: Small ActiveRecord STI Gotcha Feed Title: Obie On Rails (Has It Been 9 Years Already?) Feed URL: http://jroller.com/obie/feed/entries/rss Feed Description: Obie Fernandez talks about life as a technologist, mostly as ramblings about software development and consulting. Nowadays it's pretty much all about Ruby and Ruby on Rails. Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Obie Fernandez Latest Posts From Obie On Rails (Has It Been 9 Years Already?)

Discovered and submitted a Ruby on Rails bug today. The 'type' column on your ActiveRecord table is used by Rails magically to do single-table inheritance. You must make sure that the type column is wide enough to hold the longest subclass name or you'll run into a nasty little bug.

My table had its type column defined as VARCHAR(32). One of the subclasses is named ProductSpecificationQualityAttribute, 36 characters!!! Unfortunately, Rails didn't pick up on this little problem and stored new instances with a truncated type of ProductSpecificationQualityAttri, meaning that they do not appear in query results when you try to load them back in again from the db. Doh!

An exception would be much better in this case, so adjustments can be made to the db. It took me some time to track down the problem here because my database front-end (Navicat) was only showing about half of the width of the type column, so it wasn't obvious that the values in there were being truncated.