how can i create a invoice number

[searain]

i would like to create an invoice number. unique, increase, not too long. better, if it can have the year, month, day information too. that will be better.

some database has the feature to automatically assign the increased record number such as MS SQL server. So I can use that "increased record number" to be the invoice number, maybe also plus use the date information in the invoice number.

but the database i am using now, don't have this feature.

i have been thinking about to use a counter, everytime, when i need to assign an invoice number i will get one number and increase the counter value.

the counter could be saved in a database or in the text doc on the server.

it is kind redundancy that everytime i have to read from database or read from a text doc of the counter and write it back to the database or the text doc.

any other better ideas?

thanks.

[tomhath]

What database are you using. Mysql has the mysql_insert_id function

[searain]

Hi, I am using interbase 6.0 or firebird.

[shawon22]

i just grabbed this from zend.com u could try this out

<?php
function get_md5_unique_id(){ 
mt_srand ((double) microtime() * 1000000); 
return $unique_id = md5(uniqid(mt_rand(),1)); 
}// end get_md5_unique_id 

function get_unique_id($length=32, $pool=""){ 
// set pool of possible char 
if($pool == ""){ 
  $pool = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
  $pool .= "abcdefghijklmnopqrstuvwxyz"; 
  $pool .= "0123456789"; 
}// end if 
mt_srand ((double) microtime() * 1000000); 
$unique_id = ""; 
for ($index = 0; $index < $length; $index++) { 
  $unique_id .= substr($pool, (mt_rand()%(strlen($pool))), 1); 
}// end for 
return($unique_id); 
}// end get_unique_id 

?> 

[Weedpacket]

Increasing number, and maybe time/date info as well... hmm....
A convenient way to get a wee 12-character number (hex string) would be base_convert(date('Ymdhis'),10,16);. That would generate a new, unique, strictly increasing ID every second. It's easy enough to convert it back into something from which date/time information can be extracted (base_convert again). Of course, it's hardly secure if that's an issue 🙂. Using a higher base than 16 will allow shorter strings.

If one fresh serial# per second is not enough, you can tack on a few more digits, four say:

$serialno .= substr("0000".base_convert($i, 10, 16)), -4);

This will give you 65536 (for $i equal to 0 through to 65535) serial numbers for each timestamp. Whichever base you use (if you don't use 16) and whichever number of extra characters you use (if you don't use 4), $i would run from 0 to pow(base,num_chars)-1 inclusive.

If you don't want to have to keep track of $i is at the moment, not a problem. Tack microseconds on instead (whether this is reliable enough is platform dependent)

list($msec, $sec)=explode(' ',microtime());
$datestr = date('Ymdhis', $sec).sprintf("%06d",$msec);
$serialno = base_convert($datestr, 10, 16);