I'm stuck with this logic proble.m - php

Question

WHAT I HAVE:
-I have a file with various products ( Flag "P" mean reserved, without "P" mean sold but not reserved)
ELEMENTS
PRODOTTO Quantita Terminale
TAMOXIFENE EG*20CPR RIV 20MG 00002n 04
FERRITIN COMPLEX*OS 10FL 8ML 00001 P 01
VOLTADOL*10CER MEDIC 140MG 00001n 05
LEDERFOLIN*10CPR 7,5MG 00002 P 03
-From this file,through a regular php expression (that search only strings with "P" flag), I extract products and insert it into mysql db.
insericineldb.php
$txt = file_get_contents('./FILE', true);
$specialChars = preg_quote( '#$%^&*()+=-[]\';,./{}|\":<>?~', '#' );
preg_match_all('#([0-9]{4,9}\s+[A-Z]{1}\s+([' . $specialChars . 'A-Z0-9 ]+)\s+([0-9]{3,7})n?\s+P\s+([0-9]+))#', $txt, $match);
$products = [];
foreach (array_keys($match[2]) as $idx) {
$tagliaprodotto = rtrim(substr($match[2][$idx],1));
$tagliaquantita = ltrim($match[3][$idx],'0');
$products[] = [
'prodotto' => $tagliaprodotto,
'quantita' => $tagliaquantita,
'terminale' => $match[4][$idx]
];
}
$query = $pdo->prepare('INSERT INTO tabella (prodotto, quantita, terminale, data) VALUES (:prodotto, :quantita, :terminale, NOW()) ON DUPLICATE KEY UPDATE quantita = VALUES(quantita), terminale = VALUES(terminale)');
foreach ($products as $product) {
$query->execute($product);
}
-I extract products automatically thanks to the use of a batch (which monitors the variation of the file).
BATCH
#echo off
:loop
timeout -t 1 >nul
for %%i in (c:\file) do echo %%~ai|find "a">nul || goto :loop
"c:\xampp\php\php.exe" -f c:\xampp\htdocs\inseriscineldb.php
rem do workload
attrib -a c:\file
goto :loop
The file:
-At a certain time NOT REGULAR (when they make the final order, 2 times a day) is emptied NOT COMPLETELY (some strings with and without "P" remain in the file but they aren't important, are important only for logic because I can't use an if as: when P=0 don't start the query).
-Furthermore sometimes some products (ES. FERRITIN COMPLEX*OS 10FL 8ML 00001 P 01) is eliminated VOLUNTARILY (Suppose a customer wants a 50-milliliter product, i reserve it but after he wants a 8-milliliter product, the old 50 milliliters order will not be deleted from the database)
PROBLEM:
1)So if I enter products into the database through INSERT INTO when one of the elements is removed voluntarily, it isn't removed from the database.
2)However, if I use REPLACE instead of INSERT, when the file is emptied, the other elements inside the database will also be deleted and now I'm stuck.

Answer 1

A way to to this in a pretty simple manner, is to read all the elements from the Database ( with a "select * from tabella) then check which one is present into the file and delete / insert / update what you need.