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Luhn Digit Generation Oracle PL/SQL Implementation

Tim — Tue, 06 Oct 2009 11:27:06 +0000

Here's how to generate a Luhn Mod-10 Check Digit. It's implemented as a function in oracle PL/SQL. I spent 2 hours looking for this online, then decided to implement it myself since it's not that hard. Anyway, I thought I'd post it here for the next person trolling google for it. This is useful for generating credit card numbers or any other place you need a check digit.

This algorithm works by doing the same thing as the validation algorithm, but shifted over one character (the equivalent of adding a zero to a number, generating the sum & subtracting 10).

*EDIT - there was a bug in this code, i just fixed it on 12/4/2009, the old code returned 10 instead of zero. It also was only working on even numbers, sorry about that!

CREATE OR REPLACE FUNCTION generate_luhn (togen IN varchar)
RETURN number
IS
curval NUMBER := 0;
total NUMBER := 0;
everyother NUMBER := 1;

BEGIN
IF(
togen IS NULL
) then
RETURN 0;
end IF;

FOR i IN reverse 1 .. LENGTH(togen) loop
curval:=SUBSTR(togen, i, 1);
IF everyother = 1 then
everyother := 0;
curval := curval * 2;
IF(curval> 9) then
curval:=curval-9;
end IF;
else
everyother := 1;
end IF;

total := total + curval;
end loop;
IF MOD(total, 10) = 0 THEN
RETURN 0;
ELSE
RETURN 10 - MOD(total, 10);
END IF;
END generate_luhn;
/

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Postgres select replace with regular expression

Tim — Wed, 02 Jan 2008 21:22:50 +0000

Postgres seriously kicks ass, here's a quick way to do a substring based on a regular expression. A Co-worker wanted to get the first word out of a column that contained a sentence. If we were using something lame like oracle we'd have to do gymnastics to do that.

It's a one-liner in postgres.

SELECT substring('this is a sentence' FROM '^(.+?)\\s.+$')

So we're selecting out the group that is a series of characters at the start of a line (column) before a space. Epic win.

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Upgrade to Gutsy Gibbon Fast

Paul — Fri, 19 Oct 2007 03:29:34 +0000

Everyone is excited that Ubuntu 7.10 is finally out. (Have a look at the new feature tour here.)

But the servers are getting hammered, so most people are waiting on the upgrade (voluntarily or otherwise).

No need to wait! The more people who download from Bittorent, the faster your speeds! Grab it while it's hot!
Download a copy of the alternative i386 CD here via Bittorent.
Mac and 64 bit torrents can be obtained here.

Once you have the alternative CD, burn it, boot from it, select the upgrade option, and away you go.

Want to be environmentally friendly and save a CD? Try this:

Mount the ISO to /cdrom:
sudo mount -t iso9660 ubuntu-7.10-alternate-i386.iso /cdrom -o loop

Using the full path and proper name for the ISO image.
Open a terminal and type:
sudo /cdrom/cdromupgrade

Then the upgrade utility should launch and run from the CD.

Make sure you have the alternative CD and NOT the standard desktop CD.

Good luck and happy upgrading!

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Here We Are Now, Entertain Us!

jason — Fri, 06 Oct 2006 17:43:04 +0000

public class HereWeAreNowEntertainUs{

public static void main(String[] args) {

System.out.println("Here we are now, entertain us!");

}

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