CI + SQLSERVER

install PHP DLL first:
https://msdn.microsoft.com/en-us/library/cc296170(v=sql.105).aspx

CodeIgnitor: 2.2
SQL SERVER: SQL SERVER 2008 R2
PHP: 5.4
Web Server: Apache

/application/config/database.php
$db['default']['hostname'] = '.\SQLEXPRESS';
$db['default']['username'] = 'sa';
$db['default']['password'] = 'XXXXXXX';
$db['default']['database'] = 'YYYYYYY';
$db['default']['dbdriver'] = 'sqlsrv';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = FALSE;
$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;

//system/database/drivers/sqlsrv/sqlsrv_driver.php
LINE 121 – 124

function db_select()
{
return $this->_execute('USE [' . $this->database.']');
}

//application/models/brand_model.php (testing model)

class Brand_model extends CI_Model {
private $table_name = "";

public function __construct() {
$this->load->database();
$this->table_name = "[Brand]";
}

public function get(){

$query = $this->db->get($this->table_name);
return $query->result_array();

}

}