random code generator

Found this nice code generator in Zen. I was thinking of creating something similar to it but would generate 4 digits for my table's int(4) primary key. Any suggestions?

Quote:

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////
// Create a Coupon Code. length may be between 1 and 16 Characters
// $salt needs some thought.

function zen_create_coupon_code($salt="secret", $length = SECURITY_CODE_LENGTH) {
global $db;
$ccid = md5(uniqid("","salt"));
$ccid .= md5(uniqid("","salt"));
$ccid .= md5(uniqid("","salt"));
$ccid .= md5(uniqid("","salt"));
srand((double)microtime()*1000000); // seed the random number generator
$random_start = @rand(0, (128-$length));
$good_result = 0;
while ($good_result == 0) {
$id1=substr($ccid, $random_start,$length);
$query = "select coupon_code
from " . TABLE_COUPONS . "
where coupon_code = '" . $id1 . "'";

$rs = $db->Execute($query);

if ($rs->RecordCount() == 0) $good_result = 1;
}
return $id1;
}

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Okay, never thought it would be that simple. The int(4) made it easier, having no results with zeros at the start of the code. Here's my fix, using the zen_rand() function.

Quote:

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////
// Create a Custom Code. Length is 4 Digits starting from 1000

function zen_create_custom_code() {
global $db;
$code = zen_rand(1000,9999);
$good_result = 0;
while ($good_result == 0) {
$query = "select temp_id
from " . TABLE_TEMP . "
where temp_id = '" . $code . "'";

$rs = $db->Execute($query);

if ($rs->RecordCount() == 0) $good_result = 1;
}
return $code;
}

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