我想将XML中的数据导入我的mysql数据库 . 但是如果引用号已经存在，则必须跳过该行（数据库中没有重复项）：

PHP

$affectedRow = 0;

        $xml = simplexml_load_file("content.xml") or die("Error: Cannot create object");
        $date_now = date("Y-m-d H:i:s");
        $kennziffer = 0;

        foreach ($xml->children() as $row) {
            $reference_number = $row->reference_number;
            $company = $row->company;
            $title = $row->title;

            $sql = "
                INSERT IGNORE INTO api(reference_number,company,title,create_date)
                SELECT '$reference_number','$company','$title','$date_now'
                ";

            $result = mysqli_query($db, $sql);

            if (! empty($result)) {
                $affectedRow ++;
            } else {
                $error_message = mysqli_error($db) . "\n";
            }
        }

任何人都可以帮助我 .

php mysql xml