<?php
include "../root.class.php";

$db = new db_safeguard();

$check_jc_blk_res = $db->query("job_cards_tech", "SELECT * FROM job_cards_tech WHERE jc_number LIKE '%BLK-%' ORDER BY record_id DESC LIMIT 1");
if ($check_jc_blk_res->num_rows > 0) {
    $check_jc_blk_row = $check_jc_blk_res->fetch_assoc();
    $start = explode("-", $check_jc_blk_row['jc_number'])[1];
    $start++;
} else {
    $start = 1;
}
$blank_job_cards = $db->query("job_cards_tech", "SELECT * FROM job_cards_tech WHERE (jc_number = '' OR jc_number IS NULL) ORDER BY record_id ASC");

while ($blank_job_cards_row = $blank_job_cards->fetch_assoc()) {
    $db->query("job_cards_tech", "UPDATE job_cards_tech SET jc_number = 'BLK-$start' WHERE record_id = '$blank_job_cards_row[record_id]'");
    $start++;
}