如何使用php在谷歌云数据库中创建Mysql数据库连接

Question

I need to connect Mysql database into php. can you guide me how i can connect it. I am using following code but not working.

    $con = new mysqli(null, 'root', '','database_name', null, '/cloudsql/appengine-project-id:cloud-sql-instance-name' );

    if (mysqli_connect_errno()) {
       echo "Failed to connect to MySQL: " . mysqli_connect_error();  
    } 

    echo "Connected successfully";

For Codeigniter framework

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'root';
$db['default']['password'] = null;
$db['default']['database'] = 'myDatabase';
$db['default']['dbdriver'] = 'mysqli';        
$db['default']['dbprefix'] = 'grs_';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = FALSE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;
$db['default']['socket'] = '/cloudsql/appengine-project-id:cloud-sql-instance-name';