How do I generate more than one random code - php

Question

I have typed this up to generate a random code. I am trying to add them into a database as they are generated. How do i modify this code to generate x amount instead of one?
<?php
$tokens = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
$serial = '';
for ($i = 0; $i < 4; $i++) {
for ($j = 0; $j < 5; $j++) {
$serial .= $tokens[rand(0, 35)];
}
if ($i < 3) {
$serial .= '-';
}
}
echo '<p>' . $serial;
?>

Answer 1

for more precise random token. Try adding current timestamp with a text. current Timestamp itself changes every second. therefore it will mostly be unique. A random text adding at front or last can make it even more unique for users working at a same time.
UPDATE: also add a function whether that unique string exists or not.

Answer 2

A pretty cool, easy method, can be something like this too.
<?php
echo md5(microtime());
Ofcourse it is not 100% safe etc but if you need a quick and easy "RANDOM" string it could be usefull.
Concerning your question:
<?php
function genereteRandomKey($count=10)
{
$data = [];
for($i=0;$i<$count;$i++)
{
$data[] = md5(microtime());
}
return $data;
}
var_dump(generateRandomKey());

Answer 3

To do this, we edit your code slightly and wrap it within a function, like this;
function createHash($length = 4)
{
$tokens = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
$serial = '';
for ($it = 0; $it < $length; $it++) {
$serial .= $tokens[ mt_rand( 0, (strlen($tokens) - 1) )];
}
return $serial;
}
The length within the parameter can be left null and will default to 4, just in case you wanted to create longer codes.
To then create more codes, you simply loop via a for loop (Or any loop that you are using!) like so;
for ($i = 0; $i < 5; $i++) {
echo createHash() . '<br />';
}
Obviously, you won't be wishing to echo them out, but instead adding them to a database.
With that in mind, may I also suggest that instead of multiple INSERT queries, to catch them all inside of an array and just do one run on the query, which can be achieved like so;
$inserts = array ();
for ($i = 0; $i < 5; $i++) {
$inserts[] = createHash();
}
$sql = "INSERT INTO `table` (`row`) VALUES ('" . implode('\'), (\'', $inserts) . ");";
Which, in that test run, would output the following as your $sql;
INSERT INTO `table` (`row`) VALUES ('ISS7'), ('SB72'), ('N97I'), ('1WLQ'), ('TF6I);