我正好做了类似的事情,给你参考:
require 'rubygems'
require 'active_record'
$conn_db = { 
	:adapter => "mysql2",  
	:host => "192.168.3.199",  
	:database => "aaa_db",
	:username => "root",
	:password => "pppppp",
	:pool => 5
} 
class MyTable < ActiveRecord::Base
	establish_connection $conn_db;
end
.... [其他ruby代码]