laravel unique id
function generateBarcodeNumber() {
$number = mt_rand(1000000000, 9999999999); // better than rand()
// call the same function if the barcode exists already
if (barcodeNumberExists($number)) {
return generateBarcodeNumber();
}
// otherwise, it's valid and can be used
return $number;
}
function barcodeNumberExists($number) {
// query the database and return a boolean
// for instance, it might look like this in Laravel
return User::whereBarcodeNumber($number)->exists();
}