MySQL::SetError PHP Method

    private function SetError($errorMessage = "", $errorNumber = 0)
    {
        try {
            if (strlen($errorMessage) > 0) {
                $this->error_desc = $errorMessage;
            } else {
                if ($this->IsConnected()) {
                    $this->error_desc = mysqli_error($this->mysql_link);
                } else {
                    $this->error_desc = mysqli_connect_error();
                }
            }
            if ($errorNumber != 0) {
                $this->error_number = $errorNumber;
            } else {
                if ($this->IsConnected()) {
                    $this->error_number = @mysqli_errno($this->mysql_link);
                } else {
                    $this->error_number = @mysqli_connect_errno();
                }
            }
        } catch (Exception $e) {
            $this->error_desc = $e->getMessage();
            $this->error_number = -999;
        }
        if ($this->ThrowExceptions) {
            if (isset($this->error_desc) && $this->error_desc != NULL) {
                throw new Exception($this->error_desc . ' (' . __LINE__ . ')');
            }
        }
    }