[Can't Connect Codeigniter To Oracle]

Please help! i can't connect codeigniter to Oracle

I am trying to connect Codeigniter to Oracle 11g, here are my settings

 

 

Settings in database.php:

$active_group = 'default';
   $active_record = TRUE;
   $db['default']['hostname'] = "//localhost/";
   $db['default']['username'] = 'xxxxxxx';
   $db['default']['password'] = 'xxxxxxx';
   $db['default']['database'] = 'orcl';
   $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';
   $db['default']['swap_pre'] = '';
   $db['default']['autoinit'] = TRUE;
   $db['default']['stricton'] = FALSE;

 

 

Note: I added the C:\instantclient_11_2 to environment variable to PATH.

 

Oracle :

oracle port number: 1521

oracle hostname: Home-pc

database name: orcl

 

 

Only when I run my CodeIgniter login code it shows this error message:

 

A Database Error Occurred

 

Unable to connect to your database server using the provided settings.

 

Filename: D:\xampp\htdocs\ci\system\database\DB_driver.php

 

Line Number: 124

 

But I can connect to Oracle when I run a simple php code like:

 

<?php
   $conn = oci_connect("xxxxxx", "xxxxxx","");
   if (!$conn) { 
      echo "Not connected!";
   }
   else
     echo "yahooooooooo!!!!!!!!!!";
   ?>

Result:

yahooooooooo!!!!!!!!!!