Custom SQL query without find_by_sql (See related posts)

What if you need to call a custom query in Rails? In most cases you'll be content with ditching ActiveRecord::Base.find and going with .find_by_sql. But instantiating an Active Record per row is expensive. What if you want something faster, but you still want an OO feel? Pop this in your environment.rb (or a separate file) and give this a whirl:

   1  
   2  # OO-ified connection.select_all
   3  require 'ostruct'
   4  module ActiveRecord
   5    class Base
   6      class << self
   7        def select_all(query)
   8          rows = connection.select_all(query)
   9          rows.map! do |row|
  10            row = OpenStruct.new(row)
  11            table = row.send(:table)
  12            table.each {|k, v| table[k] = select_type_cast(v) }
  13            row
  14          end
  15          rows
  16        end
  17        def select_one(query)
  18          select_all(query).first
  19        end
  20        def select_value(query)
  21          select_type_cast(connection.select_value(query))
  22        end
  23        def select_type_cast(v)
  24          return unless v
  25          if md = v.match(/^(\d{4})-(\d{2})-(\d{2})$/)
  26            Date.new(*md.captures.map(&:to_i)) rescue v
  27          elsif md = v.match(/^(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})$/)
  28            Time.local(*md.captures.map(&:to_i)) rescue v
  29          elsif v =~ /^\d+$/
  30            v.to_i
  31          elsif v =~ /^\d+(?:\.\d+)+$/
  32            v.to_f
  33          else
  34            v
  35          end
  36        end
  37      end
  38    end
  39  end