how to connect to oracle oci 8

[eluser]Unknown[/eluser]
HI everybody.

I have been using CI with mysql for as long as 6 months,
now i want to connect with oracle 10g
Can anybody please help me to connect to oracle database.
I want to use SCOTT/TIGER@orcl tables to access.

[eluser]411161[/eluser]
Here is my database.php Notice what I commented out. One of those statements cause me not to be able to connect. I believe the db_debug was the culprit. But then I would conenct but

$db['default']['hostname'] = "localhost";
$db['default']['username'] = "as411161";
$db['default']['password'] = "as411161";
$db['default']['database'] = "vcpdb";
$db['default']['dbdriver'] = "oci8";
/*
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";
$db['default']['dbcollat'] = "utf8_general_ci";
*/

I do see posts out there like this one:
http://ellislab.com/forums/viewthread/63301/

[eluser]Unknown[/eluser]
I use this configurations :
$db['default']['hostname'] = "//127.0.0.1/ORCL";
$db['default']['username'] = "SCOTT";
$db['default']['password'] = "TIGER";
$db['default']['database'] = "ORCL";
$db['default']['dbdriver'] = "oci8";
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = FALSE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";
$db['default']['dbcollat'] = "utf8_general_ci";