An extra special case

A couple of months ago I ran into a weird issue in my current Rails project that made no sense at all. All we did was add a lock_version field to a model to enable optimistic locking and suddenly things started breaking in a big way. After a bit of digging we found it was because ActiveRecord wasn't properly quoting a table name when updating a record with optimistic locking. I submitted a patch for that issue (so it's fixed in Rails 2.1), but lately I've seen a few similar bugs having to do with table name quoting in various circumstances. The amusing thing to me is that all of these bugs have one thing in common: they were uncovered by creating a model named Reference.

At first I thought this was a pretty big coincidence, but after just a moment's thought it seemed pretty obvious. ActiveRecord pluralizes model names to form conventional table names, and references is a reserved keyword in MYSQL. I guess Reference is a word that makes a good model name, especially if you're building a big data graph and can't think of a more specific relationship name, and it's about the only noun that pluralizes into a reserved keyword that anyone would ever use. In our case, we could have done a rename refactoring to change the model class name to CharacterReference. Instead we used an override and changed the table name to t_references, since that seemed like the least effort for a temporary workaround until the fix got released with Rails 2.1.

All these various issues with table name quoting are indeed bugs in ActiveRecord and should be reported and fixed. (There's also a major reworking of the internals of ActiveRecord in progress that should deal with virtually all of these issues in one fell swoop.) But in the mean time, you might want to avoid using model names that generate SQL reserved words, or just override the table name to something else.