$jobnumber = db_quick($sql);
db_query($sql);

//initializes MySQL connection object in the global scope
$dblink = MySqlConnector::getMySql();

function db_query($sql)
{
    //previously initialized MySQL connection object
    global $dblink;

    //native MySQL API call:
    return mysqli_query($dblink, $sql);
}

//in a calling class:
$repository = new GenericRepository();
$repository->getMySql()->persist($sql);
$value = $repository->getMySql()->paramQuery($sql, $param);

//GenericRepository makes a static call to the actual connector
class GenericRepository
{
    final public function getMySql()
    {
        if ($this->link === null)
            $this->link = MySqlConnector::getMySql();

            return $this->link;
    }
}

//Connector calls MySQL API
class MySqlConnector
{

    public static function getMySql()
    {
        if (null === static::$instance)
        {
            include 'include/config.php';

            //class MySql extends mysqli library
            static::$instance = new MySql(DBHOST, DBUSER, DBPASS);
        }

        return static::$instance;
    }
}

db_query($sql);

(new NamespaceGenericRepository())->getMySql()->persist($sql);