thinkphp以PDO方式连接informix数据库，怎么配置，搞了几天了，搞不定，请各位大神帮帮忙。
config.php
<?php
return array(
//'配置项'=>'配置值'
'DB_TYPE'=>'pdo',
'DB_USER'=>'cognos',
'DB_PWD'=>'cognos123',
'DB_PREFIX'=>'diy_',
'DB_DSN'=>'odbc:appplatform',
);

indexController.class.php
<?php
namespace Home\Controller;
use Think\Controller;
class IndexController extends Controller {
public function index(){

$basemanager= M('basemanager');

var_dump($basemanager);
}
}