Igor's Blog
Programming, DIY, Games, Hacks, and Tech

There are different approaches to inserting a UUID into an Oracle Database table, ranging from Java to various ways of doing it in PL/SQL (as described here). Not many of these seemed appealing to me so I came up with my own approach using a trigger.

There was a bug in earlier versions of Oracle on AIX that caused SYS_GUID() to generate non-unique IDs so if you're still on an older version and using AIX, check this Oracle Support Note first: DUPLICATE SYS_GUID generated on AIX can lead to ORA-1 errors during enqueue (Doc ID 1371805.1).
sqldev_ddl.png


Ok so triggers are a little bit like PL/SQL, but you don't have to worry about calling them, just create the trigger on a table and you're done. In my example below I assume that there is a table with the name MY_TABLE which has a column named MY_UUID of type VARCHAR2(36) that will hold the UUID.

Here's the code for the trigger...
 UUID Trigger
CREATE OR REPLACE TRIGGER MY_INSERT_UUID_TRIGGER
BEFORE INSERT ON MY_TABLE
FOR EACH ROW
DECLARE
l_sysguid varchar2(32);
BEGIN
SELECT LOWER(SYS_GUID()) into l_sysguid FROM dual;
SELECT
substr(l_sysguid, 1, 8) || '-' ||
substr(l_sysguid, 9, 4) || '-' ||
substr(l_sysguid, 10, 4) || '-' ||
substr(l_sysguid, 15, 4) || '-' ||
substr(l_sysguid, 20, 12)
INTO :new.MY_UUID FROM dual;
END;




This trigger is created so that it adds the UUID value on each insert. A local variable, l_sysguid, is used to hold the output of the SYS_GUID() call, then SUBSTR() is used to split up the value into separate parts as required for a UUID and append them with dashes.

The output of SYS_GUID() looks something like this...3F0900B5E3783798F2E0302D7120A3DF. That is a unique value, but not necessarily a RFC 4122 type UUID, but it doesn't need to be. The logic in the trigger converts all the hexadecimal letters to lower case and then creates a value would look something like...3f0900b5-e378-3798-f2e0-302d7120a3df.

Pretty simple and it works well.

-i

comments powered by Disqus
Other posts you may like...

Recent Blog Posts

A hack to create an uber jar with the Maven Shade Plugin using local jar files

Is it worth it? Apple USB-C Digital Multi AV adapter vs a cheap eBay clone

Running X11 graphical applications after changing to another user using 'sudo su'

How to stop Facebook using ad images as post sharing thumbnails

Picking lists for Atari Lynx capacitor replacement kits

Performance - 2012 Retina MacBook Pro vs 2017 MacBook Pro

Look and feel - 2012 Retina MacBook Pro vs 2017 MacBook Pro

Using math to work out the diameter of hard to reach water cooling pipes

How to get the unreachable shard in the Hinterlands in DragonAge Inquisition

Measy RC12 wireless 2.4Ghz keyboard touchpad review

Recent Galleries

Monument Valley 2 is released and does not disappoint

Space Food - Chocolate Ice Cream with Chocolate Chips

Legeod Star Wars AT-DP kit

DIY spare parts computer build with a RAIDMAX Anura case

Fake 'Lepin' brand Lego packaging

Hardwood garden bench with clear resin void filler

Fixing a 3D printer extruder that stopped heating up

Easily increase disk space in a Lenovo Ideapad 100S 14" laptop with an M.2 SSD

Making a multi-piece 3D printed solder spool holder stand

DIY indoor apartment grow light wiring

My Other Web Sites

Igor and Elise's Travels
Riverside Expressway Cam
300 George St Blogumentary

My Online Tools

UUID to OID Converter
Guru JSON-RPC Tester
Extrudifier Object Designer
Travel ┬ÁBlog

Blogs and Friends

Matt Moores Blog
Georgi's FlatPress Guide
Perplexing Permutations
The Security Sleuth
Ilia Rogatchevski
Travelling Fairy

Blog Activity

Blog Activity
Don't forget to
me for more great articles!
Don't show this again