Rails’ find_by_sql is the devil. Ninety nine percent of the time find_by_sql is unnecessary and problematic, but it’s sooo seductive. I can’t even begin to count the ways that find_by_sql can cause trouble, but here’s a few:
- Plugins like acts_as_paranoid rely on developers *not* using the back door to get around the dynamic conditions to exclude deleted rows.
- There quite a few gotchas, ie: “SELECT * FROM users JOIN another_table …” won’t work because ActiveRecord will use the last ID field, not the first.
- Logic “hidden” in find_by_sql is not reusable (as compared to a fancy association, etc)
- It offends my aesthetic sense. We all like to pretend our ORM layer isn’t leaky.. don’t we?
I remember a time when we had to use find_by_sql when we found a feature was missing from ActiveRecord. I propose that the only remaining legitimate use of ActiveRecord may be to call a stored procedure.
So, keeping with the hyperactivity theme, I suggest that we all take some ActiveRitalin: A plugin for Rails that tells ActiveRecord to chill out, and causes developers to sit and think a bit before proceeding.
ActiveRitalin makes find_by_sql private and introduces find_by_sql_with_excuse that warns upon each use. The implementation is very simple:
module ActiveRitalin
def self.append_features(klass)
super
klass.class_eval %(
def self.find_by_sql_with_excuse(excuse, sql)
RAILS_DEFAULT_LOGGER.warn("Find By Sql called with excuse: " + excuse )
find_by_sql(sql)
end
class << self
private :find_by_sql
end
)
end
end
To use, from your rails application’s root dir:
script/plugin install git://github.com/lukegalea/activeritalin.git
Think you need find_by_sql? Ask yourself the following questions:
- Can I just use :include, :select, :join, :conditions or some combination of the above?
- Should this be an association? (perhaps with :conditions and :select on it? Maybe :readonly?)
