Create Array and print it into TXT file - php

Question

UPDATE:
I get array values from $_POST['changed'].
The array structure looks like this:
Array
(
[0] => Array
(
[recid] => 1
[nachname] => Müller7777
)
[1] => Array
(
[recid] => 3
[vorname] => Maria123
)
)
I get on line #3 this error: Fatal error: Function name must be a string
$uarr=array();
foreach ($_POST['changed'] as $a) {
list($x,$k)=array_keys($a);
list($y,$v)=array_values($a);
$uarr[$y][]="$k='$v'";
}
foreach ($uarr as $k=>$v) {
$sql = "";
$sql .="UPDATE tbl SET ".join(",",$v)." WHERE recid=$k";
// send UPDATE ...
}
file_put_contents('filename2.txt', $sql);
Before I do the final database UPDATE I want to check if the created array does its job. Thats why I want to write the $sql variable first into a txt-file.
------------------------------------------------
SOLUTION:
checking if $_POST['changed'] == null is the final answer for this question.
if ($_POST['changed'] == null) {
} else {
$uarr=array();
$b = $_POST['changed'];
foreach ($b as $a) {
list($x,$k)=array_keys($a);
list($y,$v)=array_values($a);
// $x contains the `recid` key
// $y ... value
$uarr[$y][]="$k='$v'";
}
foreach ($uarr as $k=>$v) {
$sql = "";
$sql .="UPDATE tbl SET ".join(",",$v)." WHERE recid=$k";
// send UPDATE ...
}
file_put_contents('filename2.txt', $sql);
}

Answer 1

Before you run the individual UPDATE statements - yes, for each recid value you should send one statement - you could first collect all the affected values for each recid in an associative array like
$uarr=array();
foreach ($_POST['changed'] as $a) {
list($x,$k)=array_keys($a);
list($y,$v)=array_values($a);
// $x contains the `recid` key
// $y ... value
$uarr[$y][]="$k='$v'";
}
and then do another loop like
foreach ($uarr as $k=>$v) {
$sql="UPDATE tbl SET ".join(",",$v)." WHERE recid=$k";
// send UPDATE ...
}
But, of course, this will only work correctly if the $_POST('changed') array adheres to the described format and order. And, finally, so far there is nothing in this code to protect you from SQL injection.

Answer 2

Try to do it like this:
$BigArray = $_POST['changed'];
$LengthOfArray = sizeof($BigArray);
for ($i = 0; $i < $LengthOfArray ; $i++) {
$SubArray = $BigArray[$i];
// Call the update/insert here
// $SubArray['recid'] is the ID
// $SubArray['vorname'] is the name
}