Updating of my record is not working - php

Question

I am almost close to complete my project but I have two issues which may be unable to fix please can anyone guide me, I really need help. The issue I am facing is that when I try to update "first name" or "last name" then I am getting an error, and the image path saved in the database is getting deleted. But if I try to update my image then it`s working fine. The second issue is that when I try to update my image the old image is not getting replaced with the new one, even the old image is avaliable in the folder. How to solve this two issues please I really need help .
From.php (controller part)
public function updatedata()
{
$id=$this->input->get('id');
$result['data']=$this->Form_model->displayrecordsById($id);
$this->form_validation->set_rules('fname', 'First name', 'required');
$this->form_validation->set_rules('lname', 'Last name', 'required');
$this->form_validation->set_rules('username', 'Username', 'required|min_length[5]|max_length[12]');
$this->form_validation->set_rules('email', 'Email', 'required|valid_email');
if ($this->form_validation->run() == FALSE)
{
$this->load->view('update_records',$result);
} else {
$config['upload_path'] = './uploads/';
$config['allowed_types'] = 'gif|jpg|png';
$this->load->library('upload', $config);
$fn=$this->input->post('fname');
$ln=$this->input->post('lname');
$un=$this->input->post('username');
$em=$this->input->post('email');
if($this->upload->do_upload('filename'))
{
$fi= $this->upload->data('file_name');
$unlink = unlink('uploads/' . $row->filename);
} else {
$fi= $result['data']->filename;
}
$this->Form_model->updaterecords($fn,$ln,$un,$em,$fi,$id);
echo 'Successfully updated your record';
//exit();
}
}

Answer 1

The first obvious issue is that $row var doesn't exist. In context it should be $result['data']->filename. And for your first question I don't see how updating fname and lname would logically lead to the previously uploaded file getting deleted unless another image is uploaded as do_upload will fail if no file is uploaded and thus enter your else statement.
Here I rearranged some things and added encrypt_filename. The primary purpose of this is to avoid issues where a user upload an image with the same name as a previously uploaded image even though the images might be different.
public function updatedata() {
$id = $this->input->get('id');
if (is_null($id)) {
show_error('Id cannot be empty');
}
$result['data'] = $this->Form_model->displayrecordsById($id);
$this->form_validation->set_rules('fname', 'First name', 'required');
$this->form_validation->set_rules('lname', 'Last name', 'required');
$this->form_validation->set_rules('username', 'Username', 'required|min_length[5]|max_length[12]');
$this->form_validation->set_rules('email', 'Email', 'required|valid_email');
if ($this->form_validation->run() == FALSE) {
$this->load->view('update_records', $result);
} else {
$config['encrypt_name'] = true; // highly recommended
$config['upload_path'] = './uploads/';
$config['allowed_types'] = 'gif|jpg|png';
$this->load->library('upload', $config);
$fi = $result['data']->filename;
if ($this->upload->do_upload('filename')) {
if (is_file('./uploads/' . $fi)) {
#unlink('./uploads/' . $fi);
}
$fi = $this->upload->data('file_name'); // set var to new name
}
$fn = $this->input->post('fname');
$ln = $this->input->post('lname');
$un = $this->input->post('username');
$em = $this->input->post('email');
$this->Form_model->updaterecords($fn, $ln, $un, $em, $fi, $id);
echo 'Successfully updated your record';
}
}