在布尔错误上调用成员函数fetch_array（）

Question

我收到此错误，有人可以帮我解决一下吗？

Fatal error: Call to a member function fetch_array() on boolean in /Applications/XAMPP/xamppfiles/htdocs/RECORD BREAKERS/includes/connection.php on line 33

这是代码     

require_once("connection.php");

class genre
{
    private $sGenreName;
    private $iGenreID;

    public function __construct()
    {
        $this->sGenreName=" ";
        $this->iGenreID=0;
    }
    public function getGenre($sGenreID)
    {

//make coonection
    $oConnection = new Connection();


    //create query
    $sSQL = "SELECT GenreName,GenreID from tbgenres where GenreID=2";


    //execute
    $oResultSet=$oConnection->query($sSQL);

    //fetch data
    $aRow=$oConnection->fetchArray($oResultSet);

        $aRow=$oConnection->fetchArray($oResultSet);
        $this->sGenreName=$aRow["GenreName"];
        $this->sGenreName=$aRow["GenreID"];

    }
    public function __get($var)
    {
        switch ($var) {
            case 'GenreName':
            return  $this->sGenreName;
            break;
            case 'GenreID':
            return  $this->sGenreID;
            break;
        }
    }
}


$g=new genre();
$g->getGenre(2);
echo $g;

?>