I`m trying use "$this->input->post();" of Codeigniter to do not need specify each field in my form. But i`m getting troubles when try insert into Database.

Look my controller:

```
public function cadastrar(){
        $var = $this->input->post(null, TRUE);
        $this->load->model('m_clientes');
        $this->m_clientes->inserir($var);
}

```

My controller is simplified here because i know how to handle database in codeigniter.
The result of this post was:

```
  Array ( [nome] => Raphael [sobrenome] => Schubert [cpf] => 893.528.432-89 [rg] => 4529875231908472 [telefone] => (53) 2980-5792 [celular] => (53) 9 2180-7529 [rua] => Israel de Almeida [numero] => 859 [cep] => 88.312-000 [bairro] => São Vicente [cidade] => ITAJAÍ [estado] => Santa Catarina [email] => rfswdp@gmail.com [tipo] => pf [cnpj] => 34.827.481/2834-78 [inscricaoestadual] => 34120489032814930128 [razaosocial] => Teste [nomefantasia] => Disney [dataaberturaempresa] => 10/21/15 [proprietario] => Marcos Aurelio )

```

I normaly use this way to insert:

```
$data = array(
'user_name' => $this->input->post('user_name',TRUE);
'user_phone' => $this->input->post('user_phone',TRUE);
'user_role' => $this->input->post('user_role',TRUE);
);
$this->name_of_model->inserir($data);

```

And works...

But i was trying to use just $this->input->post(); to get all fields from form. Because my actualy application will have hundreds of fields and i was trying to do not write each line.

So my model actually was:

```
   public function inserir($var){
        if($var!=NULL):
            print_r($var);
            $this->db->insert('tb_usuarios',$var);
        endif;
    }

```

But i`m getting and error saying:

Message: Undefined property: Clientes::$db
and
Message: Call to a member function insert() on null

My table name is: "tb\_usuarios"
I changed all fields in database to accept NULL to see if i`m get some field name wrong... but not work...

Any tips??