How to Create a custom Database connection in Magento?

Create a connectdb.php file in your root folder. And paste the following code. Now 

you are able to access Data base on your file.

1. require_once ("app/Mage.php");

2. $app = Mage::app('default');

3. $config  = Mage::getConfig()->getResourceConnectionConfig("default_setup"); 

4. $dbinfo = array("host" => $config->host, "user" => $config->username,"pass" => $config->password, "dbname" => $config->dbname); 

5. $hostname = $dbinfo["host"];

6. $user = $dbinfo["user"];

7. $password = $dbinfo["pass"];

8. $dbname = $dbinfo["dbname"];

9. $con = mysql_select_db($dbname,mysql_connect($hostname,$user,$password));