Validating credentials and password check

[eluser]Unknown[/eluser]
I need to integrate my login validation with my form validation and database check--need some help with it:

The validation function from my controller:

Code:

function credentials()
{
  $this->load->model('users_model');
  $query = $this->users_model->validate();
  
  if($query)
  {
   $data = array(
    'email' => $this->input->post('email'),
    'is_logged_in' => true
   );
   $this->session->set_userdata($data);
   redirect('dashboard');
  }
  else // incorrect username or password
  {
   $this->index();
  }
}

My code for the model:

Code:

function validate()
{
  $this->db->where('email', $this->input->post('email'));
  $this->db->where('password', $this->input->post('password'));
  
  $query = $this->db->get('users');
  
  if($query->num_rows == 1)
  {
   return true;
  }
    
}

Issue #1: my login form won't accept an email address that's not in the database (so the validation on the email is working), but the login form will accept any passwords or even a blank field! I don't have any security on the passwords right now (SHA2, etc.), as I'm just trying to get my arms around the basics (later I plan to use bcrypt). I've been testing out solutions for a couple of hours with no luck.

Issue #2: I have form validation fields that I would like to integrate with this function; I have the code for the form validation, but need help integrating it in with the functions above. Here's the code:

Code:

$this->load->library('form_validation');
    $this->form_validation->set_rules('email', 'email', 'required|valid_email');
    $this->form_validation->set_rules('password', 'password', 'required|min_length[8]');
            
    $this->_email = $this->input->post('email');
    $this->_password = $this->input->post('password');
            
    if($this->form_validation->run() == FALSE)
    {
        $this->index();
    }
    else
    {
        $this->load->view('hello');
    }

Thanks in advance.