CodeIgniter配置之database.php用法实例分析(2)

public function __construct($group_name = '') { parent::__construct(); if($group_name == '') { $db_conn_name = 'db'; } else { $db_conn_name = 'db_'.$group_name; } $CI = & get_instance(); if(isset($CI->{$db_conn_name}) && is_object($CI->{$db_conn_name})) { $this->db = $CI->{$db_conn_name}; } else { $CI->{$db_conn_name} = $this->db = $this->load->database($group_name, TRUE); } }