dsnless.rb

require 'dbi'
require 'dbd_odbc_patch'

dbh = DBI.connect("dbi:ODBC:DRIVER=FreeTDS;SERVERNAME=dbservername;DATABASE=MyDBName", "username", "password")

sth = dbh.prepare("select 1")
sth.execute
while row=sth.fetch do
  p row
end
sth.finish