select fails in custom model codeigniter 2 - codeigniter

Question

I have a problem with database select function, in my custom model. This is the code
class MY_Model extends CI_Model
{
public function __construct()
{
parent::__construct();
$this->load->database();
$this->load->helper('inflector');
}
public function fetch($parameters = array(), $raw = FALSE)
{
$tablename = $this->getTableName();
$this->select_fields(FALSE == empty($parameters['fields']) ? $parameters['fields'] : FALSE);
unset($parameters['fields']);
if (FALSE == empty($parameters['limit'])) $limit = $parameters['limit'];
if (FALSE == empty($parameters['offset'])) $offset = $parameters['offset']; else $offset = 0;
unset($parameters['limit']);
unset($parameters['offset']);
if (FALSE == empty($limit))
{
$this->db->limit($limit, $offset);
}
$this->parseFilters($parameters);
$query = $this->db->get($tablename);
if ($query->num_rows() > 0)
{
if ($raw)
return $query;
$rows = $query->result();
$objects = array();
foreach ($rows as $row)
$objects[] = $this->hidrate($row);
return $objects;
}
else
{
return array();
}
}
protected function select_fields($fields)
{
if (TRUE == empty($fields))
{
$fields = "`" . $this->getTableName() . "`.*";
}
$this->db->select($fields);
}
public function fetchOne($parameters = array())
{
$parameters['limit'] = 1;
$list = $this->fetch($parameters);
if (FALSE == empty($list))
{
return reset($list);
}
else
{
return null;
}
}
Expecifict in $this->db->select($fields);
Fatal error: Call to a member function select() on a non-object
The model is a custom model and the applicacions model extends of this model. The question is why throws that error the database is correct.
I have a MY_loader create in codeginiter 1.7 and I try update to codeigniter 2
class MY_Loader extends CI_Loader
{
function model($model, $name = '', $db_conn = FALSE)
{
if (is_array($model))
{
foreach($model as $babe)
{
$this->model($babe);
}
return;
}
if ($model == '')
{
return;
}
if ( substr($model, -4) == '_dao' )
{
return parent::model('dao/' . $model, $name, $db_conn);
}
parent::model( 'dao/' . $model . '_dao', $model, $db_conn);
include_once APPPATH . '/models/' . $model . EXT;
}
}
I don't know how update this model to codeigniter 2 and I believe this Loader generates error with my MY_Model

Answer 1

I'll try troubleshooting why does db return as a non-object.
I'd remove all code and start with a simple select(), if that works, I'll start adding code gradually and see where it breaks.
everything seems to be in order but first you'll need to see if the basic functionality exists.
so
1)remove all code, see if a basic select() works, if it doesn't, troubleshoot further.
2)if it does, keep adding code and see what breaks the select() statement.
3)keep adding code until you spot the issue.