问$this->load->db()；在类构造函数中初始化？

EN

public function __construct()
{
    // placing it here fails: $this has no `load` property yet.
    // $this->load->database(); <!-- NO WAY JOSÉ!
    parent::__construct();
    // placing it here should work as the parent class has added that property
    // during it's own constructor
    $this->load->database();
}

public function __construct()
{
    // Doesn't matter where this goes:
    // grab the controller directly
    $CI =& get_instance(); // & is not strictly necessary, but still...
    // force the loader to load the database.
    $CI->load->database();
    // directly assign it.
    $this->db = $CI->db;
    // continue on your merry way
    parent::__construct();
}

   $autoload['libraries'] = array('database');

$this->load->database();

$this->db->method_name();