如何从登录连接到数据库CI

Question

如何使用表单登录连接到数据库，因此用户名和密码将从登录表单中存储。我不想在 database.php 中设置默认用户名和密码;它应该来自用户登录表单。

这是我的模特

function connect(){
        $nik=$this->input->post('nik');
        $password=$this->input->post('password');

    $config['hostname'] = 'localhost';
    $config['username'] = $nik;
    $config['password'] = $password;
    $config['database'] = 'test';
    $config['dbdriver'] = 'postgre';
    $config['dbprefix'] = '';
    $config['pconnect'] = TRUE;
    $config['db_debug'] = TRUE;
    $config['cache_on'] = FALSE;
    $config['cachedir'] = '';
    $config['char_set'] = 'utf8';
    $config['dbcollat'] = 'utf8_general_ci';
    $config['swap_pre'] = '';
    $config['autoinit'] = TRUE;
    $config['stricton'] = FALSE;
    $config['port']=5432;
    //$_SESSION['conn'] = $db;  
    $dbo= $this->load->database($config,TRUE);  
    //redirect('user/index');


 //end connecting

这是我的控制器。

        function login(){
        $this->load->model("databaseconnection");
        $this->databaseconnection->connect();
        $dbo= $this->load->database($config,TRUE);  
        if (!$dbo) {
                    echo "not";
            }else{ 
                echo "ok";

                }
                            }

所以我想访问数据库到控制器，但仍然是错误。非常需要你的帮助